Armed conflict in eastern Ukraine erupted in early 2014 following Russia’s annexation of Crimea. The previous year, protests in Ukraine’s capital, Kyiv, against Ukrainian President Viktor Yanukovych’s decision to reject a deal for greater economic integration with the European Union (EU) were met with a violent crackdown by state security forces. The protests widened, escalating the conflict, and President Yanukovych fled the country in February 2014.
One month later, in March 2014, Russian troops took control of the Ukrainian region of Crimea. Russian President Vladimir Putin cited the need to protect the rights of Russian citizens and Russian speakers in Crimea and southeast Ukraine. Russia then formally annexed the peninsula after Crimeans voted to join the Russian Federation in a disputed local referendum. The crisis heightened ethnic divisions, and two months later, pro-Russian separatists in the eastern Ukrainian regions of Donetsk and Luhansk held their own independence referendums.
Armed conflict in the regions quickly broke out between Russian-backed forces and the Ukrainian military. Russia denied military involvement, but both Ukraine and the North Atlantic Treaty Organization (NATO) reported the buildup of Russian troops and military equipment near Donetsk and Russian cross-border shelling immediately following Crimea’s annexation. The conflict transitioned to an active stalemate, with regular shelling and skirmishes occurring along frontlines separating Russian- and Ukrainian-controlled eastern border regions.
Beginning in February 2015, France, Germany, Russia, and Ukraine attempted to kickstart negotiations to bring an end to the violence through the Minsk Accords. The agreement framework included provisions for a ceasefire, withdrawal of heavy weaponry, and full Ukrainian government control throughout the conflict zone. Efforts to reach a diplomatic settlement and satisfactory resolution, however, were largely unsuccessful.
In April 2016, NATO announced the deployment of four battalions to Eastern Europe, rotating troops through Estonia, Latvia, Lithuania, and Poland to deter possible future Russian aggression elsewhere on the continent, particularly in the Baltics. In September 2017, the United States also deployed two U.S. Army tank brigades to Poland to further bolster NATO’s presence in the region.
In January 2018, the United States imposed new sanctions on twenty-one individuals–including a number of Russian officials–and nine companies linked to the conflict in eastern Ukraine. In March 2018, the U.S. Department of State approved the sale of anti-tank weapons to Ukraine, the first sale of lethal weaponry since the conflict began. In October 2018, Ukraine joined the United States and seven other NATO countries in a series of large-scale air exercises in western Ukraine. The exercises came after Russia held its own annual military exercises in September 2018, the largest since the fall of the Soviet Union.
In October 2021, months of intelligence gathering and observations of Russian troop movements, force build-up, and military contingency financing culminated in a White House briefing with U.S. intelligence, military, and diplomatic leaders on a near-certain mass-scale Russian invasion of Ukraine. The only remaining questions were when the attack would take place and whether the United States would be able to convince allies to act preemptively. Both were answered on February 24, 2022, when Russian forces invaded a largely unprepared Ukraine after Russian President Vladimir Putin authorized a “special military operation” against the country. In his statement, Putin claimed that the goal of the operation was to demilitarize and denazify Ukraine and end the alleged genocide of Russians in Ukrainian territory.
In the days and weeks leading up to the invasion, the Joe Biden administration made the unconventional decision to reduce information-sharing constraints and allow for the broader dissemination of intelligence and findings, both with allies—including Ukraine—and publicly. The goal of this strategy was to bolster allied defenses and dissuade Russia from taking aggressive action. Commercial satellite imagery, social media posts, and published intelligence from November and December 2021 showed armor, missiles, and other heavy weaponry moving toward Ukraine with no official explanation from the Kremlin. By the end of 2021, more than one hundred thousand Russian troops were in place near the Russia-Ukraine border, with U.S. intelligence officials warning of a Russian invasion in early 2022. In mid-December 2021, Russia’s foreign ministry called on the United States and NATO to cease military activity in Eastern Europe and Central Asia, commit to no further NATO expansion toward Russia, and prevent Ukraine from joining NATO in the future. The United States and other NATO allies rejected these demands and threatened to impose severe economic sanctions if Russia took aggressive action against Ukraine.
In early February 2022, satellite imagery showed the largest deployment of Russian troops to its border with Belarus since the end of the Cold War. Negotiations between the United States, Russia, and European powers—including France and Germany—failed to bring about a resolution. In late February 2022, the United States warned that Russia intended to invade Ukraine, citing Russia’s growing military presence at the Russia-Ukraine border. President Putin then ordered troops to Luhansk and Donetsk, claiming the troops served a “peacekeeping” function. The United States responded by imposing sanctions on the regions and the Nord Stream 2 gas pipeline a few days later. Nevertheless, just prior to the invasion, U.S. and Ukrainian leaders remained at odds regarding the nature and likelihood of an armed Russian threat, with Ukrainian officials playing down the possibility of an incursion and delaying the mobilization of their troops and reserve forces.
On February 24, 2022, during a last-ditch UN Security Council effort to dissuade Russia from attacking Ukraine, Putin announced the beginning of a full-scale land, sea, and air invasion of Ukraine targeting Ukrainian military assets and cities across the country. U.S. President Joe Biden declared the attack “unprovoked and unjustified” and issued severe sanctions against top Kremlin officials, including Putin and Russian Foreign Minister Sergey Lavrov; four of Russia’s largest banks; and the Russian oil and gas industry in coordination with European allies. On March 2, 141 of 193 UN member states voted to condemn Russia’s invasion in an emergency UN General Assembly session, demanding that Russia immediately withdraw from Ukraine.
Since the 2014 annexation of Crimea, Ukraine has also increasingly been the target of thousands of cyberattacks. In December 2015, more than 225,000 people lost power across Ukraine in an attack on electricity generation firms, and, in December 2016, parts of Kyiv experienced another power blackout following a similar attack targeting a Ukrainian utility company. In June 2017, government and business computer systems in Ukraine were hit by the NotPetya cyberattack, which has been attributed to Russia; the attack spread to computer systems worldwide and caused billions of dollars in damages. In February 2022, Ukrainian government websites, including the defense and interior ministries, banking sites, and other affiliated organizations were targeted by distributed denial-of-service attacks alongside the Russian invasion.
The current conflict has severely strained U.S.-Russia relations and increased the risk of a wider European conflict. Tensions are likely to increase between Russia and neighboring NATO member countries that would likely involve the United States, due to alliance security commitments. The conflict will also have broader ramifications for future cooperation on critical issues like arms control; cybersecurity; nuclear nonproliferation; global economic stability; energy security; counterterrorism; and political solutions in Syria, Libya, and elsewhere. Additionally, Russia’s increasing isolation has not only destabilized global energy and resource markets but also pushed the country to seek stronger strategic ties with those states (e.g., China) still willing to partner with it, largely in opposition to the West. The war has also compounded other global crises, with military operations and violence hindering the delivery and distribution of much-needed aid, including food, and exacerbating an already severe shortage of available global humanitarian assistance and resources.
As the initial Russian invasion slowed, long-range missile strikes caused significant damage to Ukrainian military assets, urban residential areas, and communication and transportation infrastructure. Hospitals and residential complexes also sustained shelling and bombing attacks. In late March 2022, Russia announced that it would “reduce military activity” near Kyiv and Chernihiv. By April 6, Russia had withdrawn all troops from Ukraine’s capital region. In the aftermath of the Russian withdrawal from Kyiv’s surrounding areas, Ukrainian civilians described apparent war crimes committed by Russian forces, including accounts of summary executions, torture, and rape.
On April 18, Russia launched a new major offensive in eastern Ukraine following its failed attempt to seize the capital. By May, Russian forces took control of Mariupol, a major and highly strategic southeastern port city that had been under siege since late February. Drone footage published by Ukraine’s far-right Azov Battalion revealed the brutality of the Russian offensive, which had reduced the city to rubble and caused a massive humanitarian crisis. Indiscriminate and targeted attacks against civilians in the city, including an air strike on a theater and the bombing of a maternity hospital, also amplified allegations against Russian forces for international humanitarian law violations.
Since the summer of 2022, most fighting has largely been confined to Ukraine’s east and south, with Russian cruise missiles, bombs, cluster munitions, and thermobaric weapons devastating port cities along the Black Sea and the Sea of Azov. The Russian seizure of several Ukrainian ports and subsequent blockade of Ukrainian food exports compounded an already acute global food crisis further exacerbated by climate change, inflation, and supply chain havoc. Prior to the conflict, Ukraine had been the largest supplier of commodities to the World Food Program (WFP), which provides food assistance to vulnerable populations. In July, Russia and Ukraine signed an agreement to free more than twenty million tons of grain from Russian-controlled Ukrainian ports. The first grain shipments to leave Ukraine since the Russian invasion departed from Odesa on August 1; they arrived in Russian-allied Syria on August 15, although their originally presumed destination had been Lebanon.
In mid-August, the southern shift of the war’s frontline sparked international fears of a nuclear disaster at the Zaporizhzhia nuclear plant along the Dnieper River. The largest nuclear plant in Europe, the Zaporizhzhia facility was seized by Russian forces in the earliest stages of the war. Escalating tensions between the plant’s Ukrainian staff and its Russian occupiers have also raised uncertainty regarding its continued safe operation. Fighting in the territory surrounding the facility also raises concerns that the plant could be critically damaged in the crossfire: shelling of the plant’s switchyard has already led to a city-wide black-out in Enerhodar, where the plant is located. Representatives of the International Atomic Energy Agency (IAEA), including Director General Rafael Mariano Grossi, visited the plant in early September to assess the threat of a nuclear accident. In a report [PDF] on the findings of its inspection, the IAEA called for “a nuclear safety and security protection zone” around the plant and for “all military activity” in the adjacent territory to cease immediately.
As of early September, Ukrainian forces have been able to make strong advances in the northeast and mounted a revitalized southern counteroffensive. Although Russia continues to hold onto much of Ukraine’s southeastern territory, Ukraine claims to have retaken significant territory in the Kharkiv region, surprising Russian forces and cutting off important supply lines. Russia has indicated that it plans to send reinforcements—about ten to twenty thousand soldiers—to the eastern front to combat the new Ukrainian offensive. Russia also announced a partial mobilization on September 21 to refurbish the Russian army, prompting thousands of Russians to flee amid antiwar protests, and moved to annex four occupied territories: Luhansk, Donetsk, Kherson, and Zaporizhzhia. In his speech announcing the illegal annexation of Ukrainian territory, Putin also made an overture of possible nuclear escalation, claiming that the United States had set a precedent by dropping nuclear bombs on Hiroshima and Nagasaki during World War II.
By July 2022, the UN Human Rights Office recorded over five thousand civilian deaths and over six thousand civilian injuries since Russia’s full-scale military invasion of Ukraine on February 24, 2022. The violence has internally displaced nearly seven million people and forced over six million to flee to neighboring countries, including Moldova and Poland, a NATO country where the United States and other allies are helping to accommodate the influx of refugees.
The U.S. continues to commit military assistance to Ukraine; following Ukrainian President Volodymyr Zelenskyy’s address to the U.S. Congress on March 16, 2022, Biden announced an additional $800 million in military assistance to Ukraine. Since Russia’s invasion, the United States has committed about $4.6 billion in security assistance, including heavy weapons and artillery, to the country. The United States has also dramatically increased U.S. troop presence in Europe, bringing the total to more than one hundred thousand. On September 8, 2022, U.S. Secretary of State Antony Blinken pledged continued support for Ukraine during a trip to Kyiv. The United States’ most recent installment of aid was announced in early October and included $625 million worth of arms. While the United Nations, Group of Seven member states, EU, and others continue to condemn Russia’s actions and support Ukrainian forces, Russia has turned to countries like North Korea and Iran for intelligence and military equipment.
Beginning on October 10, Russia launched its most extensive attacks on Ukraine in months, striking military and energy facilities, as well as several civilian areas during rush hour. The attacks spanned fourteen regions and included assaults on the capital. This renewed Russian offensive comes after Ukrainian forces destroyed part of the only bridge connecting the occupied Crimean Peninsula to Russia.
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