onslaught Kyiv residents told to 'make Molotov cocktails' as they get ready fight Putin's army

Russian troops are bearing down on Ukraine's capital, with gunfire and explosions resonating ever closer to the government quarter, in an invasion of a democratic country that has fuelled fears of wider war in Europe.

Amid growing casualties - including shelling that sliced through a Kyiv apartment building, bridges and schools - were increasing signs that Moscow may be seeking to overthrow Ukraine's government, in Vladimir Putin's boldest effort yet to redraw the world map and revive Moscow's Cold War-era influence.

Ukrainian military vehicles are entering the country's capital Kyiv to defend it against approaching Russian troops, Ukraine's interior ministry said on Friday.

Ukrainian forces lined up on approaches to the capital to greet the approaching Russian forces and residents were urged to make Molotov cocktails to defend themselves against the predicted onslaught later today.

Kyiv's mayor Vitali Klitschko said earlier the city had "entered into a defensive phase".

Ukrainian authorities used armoured vehicles and snowploughs to defend Kyiv and limit movement, and said Russian spies were seeking to infiltrate the city.

Russia's military said it had seized a strategic airport outside Kyiv that would allow it to quickly build up forces to take the capital.

It claimed to have already cut the city off from the west - the direction most of those escaping the invasion are heading in, with lines of cars snaking towards the Polish border.

Intense fire broke out on a bridge across the Dnipro River dividing the eastern and western sides of Kyiv, with about 200 Ukrainian forces establishing defensive positions and taking shelter behind their armoured vehicles and later under the bridge.

Missiles pounded the Ukrainian capital on Friday as Russian forces entered the capital and Ukrainian President Volodymyr Zelenskiy pleaded with the international community to do more, saying sanctions announced so far were not enough.

Air raid sirens wailed over the city of 3 million people, where some were sheltering in underground metro stations.

Ukrainian troops are defending positions on four fronts despite being outnumbered, as Nato leaders prepare to meet later.

An estimated 100,000 people fled as explosions and gunfire rocked major cities. Ukraine said at least 137 Ukrainians were killed overnight and 300 injured, and said hundreds of Russians had died, although Russia released no casualty figures.

People in Kyiv were told to make Molotov cocktail petrol bombs as they hid in makeshift shelters and basements, awaiting a Russian assault on the Ukrainian capital.

"Make Molotov cocktails, neutralise the occupier!" the Defence Ministry said, while local authorities told people in the northwestern Obolon area of the city to stay off the streets because "active hostilities" were approaching.

Some residents took refuge in subway stations being used as air-raid shelters, or rushed to basements of apartments blocks or other buildings when air-raid warnings sounded.

Russian troops seized the Chernobyl former nuclear power plant north of Kyiv as they advanced on the city from Belarus, with higher than usual radiation now being recorded at the site due to soil disturbance. Earlier reports that a nuclear waste store had been damaged have been discounted.

It is now believed Russia aims to capture Kyiv and topple the government, which Putin regards as a puppet of the United States.

Zelenskiy said he understood Russian troops were coming for him but vowed to stay in Kyiv.

"(The) enemy has marked me down as the number one target," Zelenskiy said in a video message. "My family is the number two target. They want to destroy Ukraine politically by destroying the head of state."

"I will stay in the capital. My family is also in Ukraine."

He urged Europe on Friday to act more quickly and forcefully in imposing sanctions on Moscow for invading Ukraine, accusing western allies of politicking as Moscow's forces advanced on Kyiv.

"Europe has enough strength to stop this aggression," Zelenskiy said, adding that everything from banning Russians from entering the European Union to cutting Moscow off from the SWIFT international banking payments system to an oil embargo should be on the table.

"You still can stop this aggression. You have to act swiftly," he said.

A German government spokesperson said coordination among European Union leaders on another sanctions package against Russia is in the early stages.

Steffen Hebestreit said that the notion of Zelenskiy seeking political asylum in Germany was not an issue at the moment and said the government would address it if it did arise.

Russia launched its invasion by land, air and sea on Thursday following a declaration of war by Putin, in the biggest attack on a European state since World War Two.

Air raid sirens wailed over Kyiv amid unconfirmed reports that a Russian plane had been shot down and crashed into a building a day after Russian President Vladimir Putin launched an invasion that has shocked the world.

Russia has bombed 33 civilian sites in its assault on Ukraine in the last 24 hours, Kyiv's interior ministry said on Friday.

"The Russians say they are not striking civilian objects. But 33 civilian sites have been hit over the last 24 hours," said an official at Ukraine's Interior Ministry, Vadym Denysenko.

A senior Ukrainian official said Russian forces would enter areas just outside the capital, Kyiv, later on Friday and that Ukrainian troops were defending positions on four fronts despite being outnumbered.

Zelenskiy said he understood Russian troops were coming for him but vowed to stay in Kyiv.

"(The) enemy has marked me down as the number one target," Zelenskiy said in a video message. "My family is the number two target. They want to destroy Ukraine politically by destroying the head of state."

"I will stay in the capital. My family is also in Ukraine."

He said Ukraine's military had so far prevented Russia from achieving its objectives. "Russia will have to talk to us sooner or later, talk about how to end the fighting and stop this invasion," Zelenskiy said in a morning address. "The sooner this conversation begins, the smaller the losses to Russia itself."

He also ordered men of fighting age from 18 to 60 could not leave the country.

The Ukrainian foreign minister, Dmytro Kuleba, said in a tweet just before 4am on Friday that "horrific rocket strikes" hit Kyiv in an attack he compared to the city's 1941 shelling by Nazi Germany.

"Last time our capital experienced anything like this was in 1941 when it was attacked by Nazi Germany," he said.

"Ukraine defeated that evil and will defeat this one. Stop Putin. Isolate Russia. Sever all ties. Kick Russia out of (everywhere)."