KYIV, Ukraine (AP) -- Russia pressed its invasion of Ukraine to the outskirts of the capital Friday after unleashing airstrikes on cities and military bases and sending in troops and tanks from three sides in an attack that could rewrite the global post-Cold War security order.
Explosions sounded before dawn in Kyiv and gunfire was reported in several areas, as Western leaders scheduled an emergency meeting and Ukraine's president pleaded for international help to fend off an attack that could topple his democratically elected government, cause massive casualties and ripple out damage to the global economy.
Among the signs that the Ukrainian capital was increasingly threatened, the military said Friday that a group of Russian spies and saboteurs was seen in a district on the outskirts of Kyiv, and police told people not to exit a subway station in the city center because there was gunfire in the area. Elsewhere in the capital, soldiers established defensive positions at bridges, and armored vehicles rolled down the streets, while many residents stood uneasily in doorways of their apartment buildings.
U.S. Secretary of State Antony Blinken said Kyiv "could well be under siege" in what U.S. officials believe is a brazen attempt by Russian President Vladimir Putin to install his own regime.
The assault, anticipated for weeks by the U.S. and Western allies, amounts to the largest ground war in Europe since World War II. After repeatedly denying plans to invade, the autocratic Putin launched his attack on the country, which has increasingly tilted toward the democratic West and away from Moscow's sway.
Ukrainian President Volodymyr Zelenskyy, whose grasp on power was increasingly tenuous, appealed to global leaders for even more severe sanctions than the ones imposed by Western allies and for defense assistance.
"If you don't help us now, if you fail to offer a powerful assistance to Ukraine, tomorrow the war will knock on your door," said the leader, who cut diplomatic ties with Moscow, declared martial law and ordered a full military mobilization that would last 90 days.
Zelenskyy said he's the No. 1 target for the invading Russians but that he planned to remain in Kyiv. Swedish Prime Minister Magdalena Andersson said early Friday that the Ukrainian attended a meeting of European Union leaders via video link from what appeared to be some sort of bunker.
As air raids sirens sounded in the capital early Friday, guests of a hotel in the city center were directed to a makeshift basement shelter, lined with piles of mattresses and bottles of water. Workers, all local university students, served tea and cookies to the guests. Some people ducked out to a courtyard to smoke or get fresh air.
"We're all scared and worried. We don't know what to do then, what's going to happen in a few days," said one of the workers, Lucy Vashaka, 20.
The invasion began early Thursday with a series of missile strikes on cities and military bases, and then quickly followed with a multi-pronged ground assault that rolled troops in from several areas in the east; from the southern region of Crimea, which Russia annexed in 2014; and from Belarus to the north.
After Ukrainian officials said they lost control of the decommissioned Chernobyl nuclear power plant, scene of the world's worst nuclear disaster, Russia said Friday it was working with the Ukrainians to secure the plant. There was no corroboration of such cooperation from the Ukrainian side.
Zelenskyy said that 137 "heroes," including 10 military officers, had been killed, and one of his advisers said about 400 Russian forces had died. Moscow has given no casualty count. Neither claim could be independently verified.
Fearing a Russian attack on the capital city, thousands of people went deep underground as night fell, jamming Kyiv's subway stations.
At times it felt almost cheerful. Families ate dinner. Children played. Adults chatted. People brought sleeping bags or dogs or crossword puzzles -- anything to alleviate the waiting and the long night ahead.
"Nobody believed that this war would start and that they would take Kyiv directly," said Anton Mironov, waiting out the night in one of the old Soviet metro stations. "I feel mostly fatigue. None of it feels real."
Many who spent the night in makeshift bunkers, emerged in the early hours of Friday to a relatively quiet city. Some traffic and cars moved along highways, along with columns of military. The lines at fuel stations the day before had evaporated.
With social media amplifying a torrent of military claims and counter-claims, it was difficult to determine exactly what was happening on the ground.
Russia said it was not targeting cities, but journalists saw destruction in many civilian areas and Kyiv Mayor Vitaly Klitschko said a rocket hit a multistory apartment building in the city on Friday, starting a fire. Meanwhile, the mayor of the city in the rebel-controlled east said Ukrainian shelling hit a school building.
The Ukrainian military on Friday reported significant fighting near Ivankiv, about 60 kilometers (40 miles) northwest of Kyiv, as Russian forces apparently tried to advance on the capital from the north. Russian troops also entered the city of Sumy, near the border with Russia that sits on a highway leading to Kyiv from the east.
Later came the reports of at least some forces much closer.
"The hardest day will be today. The enemy's plan is to break through with tank columns from the side of Ivankiv and Chernihiv to Kyiv," Interior Ministry adviser Anton Gerashchenko said on Telegram.
Hours after the invasion began, Russian forces seized control of the now-decommissioned Chernobyl plant and its surrounding exclusion zone, presidential adviser Myhailo Podolyak told The Associated Press.
The Vienna-based International Atomic Energy Agency said it was told by Ukraine of the takeover, adding that there had been "no casualties or destruction at the industrial site."
The conflict shook global financial markets: Stocks plunged and oil prices soared amid concerns that heating bills and food prices would skyrocket. Condemnation came not only from the U.S. and Europe, but from South Korea, Australia and beyond -- and many governments readied new sanctions. Even friendly leaders like Hungary's Viktor Orban sought to distance themselves from Putin.
U.S. President Joe Biden announced new sanctions that will target Russian banks, oligarchs, state-controlled companies and high-tech sectors, saying Putin "chose this war" and had exhibited a "sinister" view of the world in which nations take what they want by force. He added that the measures were designed not to disrupt global energy markets. Russian oil and natural gas exports are vital energy sources for Europe.
Biden was to meet Friday morning with fellow leaders of NATO governments in what the White House described as an "extraordinary virtual summit" to discuss Ukraine.
British Prime Minister Boris Johnson said he aimed to cut off Russia from the U.K.'s financial markets as he announced sanctions, freezing the assets of all large Russian banks and planning to bar Russian companies and the Kremlin from raising money on British markets.
"Now we see him for what he is -- a bloodstained aggressor who believes in imperial conquest," Johnson said of Putin.
Zelenskyy urged the U.S. and West to go further and cut the Russians from the SWIFT system, a key financial network that connects thousands of banks around the world. The White House has been reluctant to do that, worried it could cause enormous economic problems in Europe and elsewhere in the West.
While some nervous Europeans speculated about a possible new world war, the U.S. and its NATO partners have shown no indication they would send troops into Ukraine, fearing a larger conflict. NATO reinforced its members in Eastern Europe as a precaution, and Biden said the U.S. was deploying additional forces to Germany to bolster NATO.
Ukrainians were urged to shelter in place and not to panic.
"Until the very last moment, I didn't believe it would happen. I just pushed away these thoughts," said a terrified Anna Dovnya in Kyiv, watching soldiers and police remove shrapnel from an exploded shell. "We have lost all faith."