Firefighters work at a damaged residential building at Koshytsa Street, Kyiv. AFP

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 as Western leaders scheduled an emergency meeting and Ukraine's president pleaded for international help. The nature of the explosions was not immediately clear, but the blasts came amid signs that the capital and largest Ukrainian city was increasingly threatened following a day of fighting that left more than 100 Ukrainians dead.

Ukrainian President Volodymyr Zelenskyy said the government had information that "subversive groups” were encroaching on the city, and US Secretary of State Antony Blinken said Kyiv "could well be under siege" in what US officials believe is a brazen attempt by Russian President Vladimir Putin to dismantle the government and install his own regime.

Zelenskyy said in a video address that 137 "heroes,” including 10 military officers, had been killed and 316 people wounded. The dead included border guards on the Zmiinyi Island in the Odesa region, which was taken over by Russians, according to the Associated Press.

Hours after the invasion began, Russian forces seized control of the now-unused Chernobyl plant and its surrounding exclusion zone after a fierce battle, 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 Ukrainian military on Friday reported significant fighting in the area of Ivankiv, about 60 kilometres (40 miles) northwest of Kyiv, as Russian forces apparently tried to advance on the capital from the north. It said one bridge across a small river had been destroyed.
"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. Russian tanks burn perfectly when hit by our ATGMs (anti-tank guided missiles),” Interior Ministry adviser Anton Gerashchenko said on Telegram.

US Defence Secretary Lloyd Austin told lawmakers on a phone call that Russian mechanised forces that entered from Belarus were about 20 miles from Kyiv, according to a person familiar with the call.

The assault, anticipated for weeks by the US and Western allies and undertaken by Putin in the face of international condemnation and cascading sanctions, amounts to the largest ground war in Europe since World War II.

Russian missiles bombarded cities and military bases in the first day of the attack, and Ukraine officials said they had lost control of the decommissioned Chernobyl nuclear power plant, scene of the world’s worst nuclear disaster. Civilians piled into trains and cars to flee.

As explosions sounded in Kyiv early on Friday, guests of a hotel were directed to a makeshift basement shelter. Air raid sirens also went off.

"Russia has embarked on a path of evil, but Ukraine is defending itself and won’t give up its freedom,” Zelenskyy tweeted. His grasp on power increasingly tenuous, he called on Thursday for even more severe sanctions than the ones imposed by Western allies and ordered a full military mobilisation that would last 90 days.

He concluded an emotional speech by saying that "the fate of the country depends fully on our army, security forces, all of our defenders.” He also said the country had heard from Moscow that ”they want to talk about Ukraine’s neutral status."

Biden was to meet on Friday morning with fellow leaders of NATO governments in what the White House described as an "extraordinary virtual summit” to discuss Ukraine.

New sanctions

US President Joe Biden announced new sanctions against Russia, saying Putin "chose this war” and had exhibited a "sinister” view of the world in which nations take what they want by force.

Other nations also announced sanctions, or said they would shortly.

"It was always about naked aggression, about Putin’s desire for empire by any means necessary - by bullying Russia’s neighbours through coercion and corruption, by changing borders by force, and, ultimately, by choosing a war without a cause,” Biden said.

Blinken said in television interviews that he was convinced that Russia was intent on overthrowing the Ukrainian government, telling CBS that Putin wants to "reconstitute the Soviet empire" and that Kyiv was already "under threat, and it could well be under siege.”

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.
But the exhaustion was clear on many faces. And the worries.

"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.”