Russia on Wednesday launched an invasion of Ukraine in what it termed a "special military operation," prompting reports of a "steady stream of loud explosions" along the borders of the two countries.
Explosions rang out in Kharkiv, Ukraine's second-largest city, and Kyiv, its capital, according to reports. Russian troops reportedly landed in Odessa, a port city in Ukraine's south.
Dmytro Kuleba, Ukraine's foreign minister, called the Russian military actions "a full-scale invasion" of his country.
"Peaceful Ukrainian cities are under strikes," Kuleba wrote on Twitter. "This is a war of aggression."
The attacks came minutes after Russian President Vladimir Putin declared the start of military operations after months of mounting tensions. During that period, Putin delivered angry speeches as Russia built up its forces along the border. Leaders in Washington and Europe sought a resolution through diplomacy, an effort that showed little progress.
Ukraine, which had been part of the Russian-led Soviet Union for much of the 20th century, declared its independence in 1991. Since then, it has been establishing closer ties with Western European nations and the US.
By this week, more than 150,000 Russian troops were said to be surrounding Ukraine.
The invasion began Thursday at around 4:30 a.m. local time, with Russian forces launching attacks from the north in Belarus, from the country's eastern border with Ukraine and from the south in Crimea. As the attacks continued throughout the day, many Ukrainian residents made preparations to flee their homeland. Countries in central Europe including Poland, Hungary and Slovakia prepared to receive an influx of refugees. A curfew will be enforced this evening in Kyiv, beginning at 10 p.m. local time.
On Thursday afternoon, Ukraine's president, Volodymyr Zelensky, tweeted that Russian forces were attempting to seize control of the Chernobyl nuclear power plant. "This is a declaration of war against the whole of Europe," he said.
Putin said the goal of the military operation is to demilitarize Ukraine but not occupy it. "For this we will aim for demilitarization and denazification of Ukraine as well as taking to court those who carried out multiple bloody crimes against civilians including citizens of the Russian Federation," Putin said in a statement, repeating discredited claims of ethnic cleansing being conducted by Ukrainian forces against ethnic Russians.
The leaders of the G7, including US President Joe Biden and UK Prime Minister Boris Johnson, issued a joint statement condemning Russia following their meeting on Thursday. "President Putin has reintroduced war to the European continent," they said. "He has put himself on the wrong side of history."
Biden said late Wednesday that the US and partners will respond in a "decisive way" and "hold Russia accountable." On Thursday, he called a meeting of the US National Security Council.
"President Putin has chosen a premeditated war that will bring a catastrophic loss of life and human suffering," Biden said in a statement. "Russia alone is responsible for the death and destruction this attack will bring."
UN Secretary-General António Guterres issued a plea to the Russian president, speaking both to journalists and on Twitter. "In the name of humanity bring your troops back to Russia," he said. "In the name of humanity to not start what may be the most devastating war since the start of the century."
NATO chief Jens Stoltenberg decried Russia's actions as "an act of aggression against a sovereign, independent and peaceful country." He added, "this is a deliberate, cold-blooded and long-planned invasion." There are currently 100 jets defending NATO airspace and 120 allied ships at sea.
The Pentagon has put 8,500 US troops on high alert to bolster NATO's response force, and Biden on Tuesday reiterated that the US will provide defensive assistance to Ukraine and reinforce its NATO allies. A virtual summit of NATO leaders is scheduled for Friday.
Building up to invasion
Russia invaded Ukraine back in 2014 before annexing Crimea. It has backed separatists in Donetsk and Luhansk, two regions in eastern Ukraine that Russia now recognizes as independent. Approximately 14,000 people have reportedly been killed in ongoing conflicts in eastern Ukraine.
Putin has previously accused the Ukrainian government, without proof, of pursuing "genocide" in Donetsk and Luhansk, whose populations are overwhelmingly ethnic Russian. But he's also lamented the collapse of the Soviet Union, which he described last year, in a documentary film called Russia: New History, as the "disintegration of historical Russia."
Putin has also long bristled at NATO's expansion into eastern Europe. The US and NATO in December rejected a Russian proposal that called for "a Cold War-like security arrangement," according to The New York Times, including demands for "ironclad" guarantees that Ukraine and Georgia never become members of NATO. The admission of either country would increase the military alliance's presence along Russia's border.
On Wednesday, Britain's ambassador to the UN accused Russia of holding Ukraine hostage and asked Russia to avoid war, saying it would have "devastating humanitarian consequences," costing lives on both sides.
"For months, Russia has been holding a gun to Ukraine's head. Now, President Putin's finger is on the trigger," United Kingdom Ambassador Barbara Woodward said Wednesday night during an emergency UN Security Council meeting requested by Ukraine. "The world is calling for peace, but Russia is not listening."
Sanctions and ramifications
In the wake of the explosions, Ukraine President Volodymyr Zelensky declared martial law, and Moex, Moscow's stock exchange, halted trading. Russia's currency, the ruble, fell nearly 3.5%, to 84.1 per dollar, its lowest level since 2016.
Earlier in the day, Zelensky made a televised appeal for peace in a dramatic last-minute effort to avert war in Eastern Europe.
"The people of Ukraine and the government of Ukraine want peace," Zelensky said during the emotional address. "But if we come under attack, if we face an attempt to take away our country, our freedom, our lives and lives of our children, we will defend ourselves. When you attack us, you will see our faces, not our backs."
On Tuesday, the European Union agreed to a package of sanctions against Russia, targeting banks that fund the country's military operations and banning trade between the EU and the two breakaway regions in eastern Ukraine. Germany also halted approval of the Nord Stream 2, a key natural gas pipeline running from Russia to Germany.
On Thursday, European Commission President Ursula von der Leyen warned of further sanctions designed to "seriously degrade the Russian economy." These include freezing Russian assets within the EU and preventing Russian banks from accessing the European market. World leaders are currently divided on whether to cut Russia off from the SWIFT global interbank payments system. The UK and some EU states support the move, while others, including Germany, have warned against it.
Boris Johnson announced on Thursday that all Russian banks would face a full asset freeze, and banned Russia's national airline Aeroflot from landing in the UK. The UK extended sanctions to Belarus for its role in assisting the Russian invasion.
Later on Thursday,in which he said the US would cut off Russian banks and stop Russia's ability to finance and grow its military. He said he had no plans to talk with Putin, who would be a "pariah" on the international stage. "Putin's aggression against Ukraine will end up costing Russia dearly economically and strategically," Biden said.
The conflict has already had global economic consequences, with the price of oil nearing $100 a barrel on Wednesday.
On Feb. 18, US officials also said they believe Russia was responsible for cyberattacks against Ukraine's banks and military earlier this month. They were the latest in a string of digital incursions that have been blamed on Russia, including attacks that defaced government websites and planted destructive malware on Ukrainian computer networks.
Earlier in January, Deputy Secretary of State Wendy Sherman pushed back on Russia's demands, saying the US would "not allow anyone to slam closed NATO's open door policy."