A battle for Ukraine’s capital Kyiv is underway after Russian troops entered the northern districts and President Vladimir Putin called on the Ukraine army to overthrow its own government.

Following an earlier bombardment of missile fire that sent families cowering in shelters, invading boots are now on the ground in the city and armoured vehicles advancing on the streets.

The attack comes as Russian troops have encountered stiffer-than-expected opposition in Ukraine and Mr Putin faces a freeze on his European assets.

As Ukraine President Volodymyr Zelenskiy vowed to defend his homeland, the defence ministry urged residents to prepare Molotov cocktails while 18,000 guns and ammunition were distributed to reservists in Kyiv.

Conscription-aged men between 18 and 60 are being restricted from crossing the border as thousands of Ukrainians continue to flee for safety in neighbouring pro-NATO nations.

Even as the fighting intensified in the city of three million people, Kremlin spokesman Dmitry Peskov said Russia was ready to send a delegation to the Belarusian capital Minsk for talks with Ukraine.

An adviser to Mr Zelenskiy said Ukraine was prepared for talks with Russia, including on staying out of the NATO allaince, one of Vladimir Putin’s pre-war demands.

Russian President Vladimir Putin urged the Ukrainian army to “take power into your own hands” saying “it will be easier for us to reach agreement”.

“I once again appeal to the military personnel of the armed forces of Ukraine: do not allow neo-Nazis and (Ukrainian radical nationalists) to use your children, wives and elders as human shields,” Mr Putin said at a televised meeting with Russia’s Security Council on Friday.

At the same time, Mr Zelenskiy tweeted a video vowing to defend the country’s independence and declaring ‘Glory to Ukraine’.

A damaged residential block hit by an early morning missile strike in Kyiv. Photo: Getty

Earlier in a speech, the Ukraine President promised to posthumously honour 13 Ukrainian guards killed defending a tiny island on the Black Sea from Russian invasion.

An audio exchange that officials say was between Russian and Ukrainian forces reveals the last words of a defiant Ukrainian defender.

“This is a Russian warship. I propose you lay down your weapons and surrender to avoid bloodshed and unnecessary victims. Otherwise you will be bombed,” the Russian invader said.

“Russian warship, go f**k yourself,” came the reply.

Mr Zelenskiy said the deceased border guards would be decorated.

“On our Zmiinyi Island, defending it to the last, all the border guards died heroically. But they did not give up. All of them will be posthumously awarded the title of Hero of Ukraine,” he said.

All 13 of the Zmiinyi Island border guards were killed after he exchange. Photo: Getty

Ukraine said more than 1000 Russian soldiers had been killed so far. Russia has not released casualty figures.

Kyiv Mayor Vitali Klitchko said the city had gone into a “defensive phase”.

“Shots and explosions are ringing out in some neighbourhoods. Saboteurs have already entered Kyiv,” said Mr Klitchko, a former world heavyweight boxing champion.

“The enemy wants to put the capital on its knees and destroy us.”

Ukrainian officials said a Russian aircraft had been shot down and crashed into a building in Kyiv overnight, setting it ablaze and injuring eight people.

Mr Zelenskiy tweeted that there had been heavy fighting with people killed at the entrance to the eastern cities of Chernihiv and Melitopol, as well as at Hostomel.

Witnesses said loud explosions could also be heard in Kharkiv.

Windows were blasted out of a 10-storey apartment block near Kyiv’s main airport, where a two-metre crater filled with rubble showed where a shell had struck before dawn.

“How we can live through it in our time?… Putin should burn in hell along with his whole family,” local resident Oxana Gulenko told reporters as she swept broken glass from her room.

Elsewhere, hundreds of people were crowded into a cramped bomb shelter beneath a building after a televised warning of air strikes.

“We don’t know how long we have to stay here. Good we have chairs at least,” said Viktoria, 35, while her children aged 5 and 7 slept without taking off their winter coats.

“We’re shocked… How can you wage a war against peaceful people?”

‘Number one’ target

US officials believe Russia’s initial aim is to topple Mr Zelenskiy and “decapitate” his government.

Mr Zelenskiy said he knew he was “the number one target” but he would stay in Kyiv.

Strengthening sanctions, concrete defense assistance and an anti-war coalition have just been discussed with @POTUS. Grateful to 🇺🇸 for the strong support to 🇺🇦!

— Volodymyr Zelenskyy / Володимир Зеленський (@ZelenskyyUa) February 25, 2022

Mr Putin says Ukraine is an illegitimate state carved out of Russia, a view Ukrainians see as aimed at erasing their more than a thousand-year history.

Mr Putin has said he does not plan a prolonged military occupation, only to disarm Ukraine and remove its leaders.

But it is not clear how a pro-Russian leader could be installed unless troops control much of the country.

Putin sanctions

European Unions nations have agreed to freeze any European assets of Mr Putin and his foreign minister Sergey Lavrov.

The EU announced the sanctions on Saturday (Australian time), as Mr Zelenskiy pleaded for faster and more forceful sanctions to punish Russia’s invasion of his country.

The move against Mr Putin came as envoys of the EU’s 27 member states agreed on a new wave of measures to tarhet Russia’s elite and thwart operations of some 70 per cent of the country’s banking system.

“We are now listing President Putin and Foreign Minister Lavrov as well,” German Foreign Minister Annalena Baerbock said.

“They are responsible for the deaths of innocent people in Ukraine, and for trampling on the international system. We, as Europeans, do not accept that,” Ms Baerbock added.

EU head of foreign policy Josep Borrell said Mr Putin now joins Syrian President Bashar al-Assad and Alexander Lukashenko of Belarus as the only world leaders sancioned by the bloc.

-with AAP