Invading forces in Ukraine pushed closer to Kyiv as efforts to evacuate 200,000 people from the heavily bombarded city of Mariupol fell apart for a second day in a row.

Another Russian push on the east bank of the Ukrainian capital's Dnipro River has seen some forces approach to within about 50 kilometres.

Russia's defence ministry released footage showing some tracked military vehicles on the move.

But the west offers the Russians a more direct route to the heart of Kyiv and its prized government district.

There is just one bridge on the western flank of the Ukrainian capital that has not been blown up in a desperate bid to slow the Russian tanks.

In the capital, Ukrainian soldiers bolstered defences by digging trenches, blocking roads with barricades and liaising with civil defence units as Russian forces bombarded areas nearby.

Elsewhere in Ukraine, police reported Russian shelling and air raids in the northeast Kharkiv region.

Moscow said it had struck and disabled Starokostiantyniv airbase in west Ukraine using high-precision weapons.

Russian President Vladimir Putin said today his campaign in Ukraine was going to plan and would not end until Kyiv stopped fighting.

His declaration came as efforts to evacuate 200,000 people from the heavily bombarded city of Mariupol fell apart for a second day in a row.

Most people trapped in the port city are sleeping in bomb shelters to escape more than six days of near-constant shelling by encircling Russian forces that has cut off food, water, power and heating supplies, according to the Ukrainian authorities.

"They're destroying us," Mariupol mayor Vadym Boychenko told Reuters in a video call, describing the city's plight before the latest evacuation effort failed.

"They will not even give us an opportunity to count the wounded and dead as the shelling does not stop."

The civilian death toll from hostilities across Ukraine since Moscow launched its invasion on 24 February stood at 364, including more than 20 children, according to the United Nations, with hundreds more injured.

The UN High Commissioner for Human Rights said most civilian casualties were caused by the use of "explosive weapons with a wide impact area, including shelling from heavy artillery and multi-launch rocket systems, and missile and air strikes."

A destroyed building after shelling in Kharkiv today

Moscow has repeatedly denied attacking civilian areas.

In Irpin, a town some 25km northwest of the capital Kyiv, men, women and children trying to escape armed clashes in the area were forced to take cover when missiles struck nearby, according to Reuters witnesses.

Soldiers and fellow residents helped the elderly hurry to a bus filled with frightened people, some cowering as they waited to be driven to safety.

The invasion has drawn almost universal condemnation around the world, sent more than 1.5 million Ukrainians fleeing from the country, and triggered tough Western sanctions against Russia aimed at squeezing its economy.

"War is madness, please stop," Pope Francis said in his weekly address to crowds in St Peter's Square, adding that "rivers of blood and tears" were flowing in Ukraine's war.

People feeling from Irpin today

President Putin made his demand for Kyiv to end the fighting in a phone call with Turkish President Tayyip Erdogan, who appealed for a ceasefire.

He told Mr Erdogan he was ready for dialogue with Ukraine and foreign partners but any attempt to draw out negotiation would fail, a Kremlin statement said.

Russian media said Mr Putin also held almost two hours of talks today with French President Emmanuel Macron.

Mr Macron told Mr Putin he was concerned about a possible imminent attack on the southern Ukrainian city of Odessa, Macron's office said.

Anti-war protests took place around the world including in Russia itself, where police detained over 4,300 people, an independent protest monitoring group said.

The interior ministry said 3,500 demonstrators had been held, included 1,700 people in Moscow and 750 in St Petersburg.

It comes as the number of refugees fleeing Ukraine has reached 1.5 million as Russia's attack continued for an 11th day and Ukraine pressed for further Western help, including more sanctions and weapons.

Ukrainians who could escape spilled into neighbouring Poland, Romania, Slovakia and elsewhere.

The United Nations said it is Europe's fastest growing refugee crisis since World War II.

"More than 1.5 million refugees from Ukraine have crossed into neighbouring countries in 10 days," the UN High Commissioner for Refugees tweeted.

Since Russia invaded on 24 February, a total of 922,400 people have fled Ukraine to Poland, Polish border guards said today.

The World Health Organization said meanwhile that signs of attacks on health centres in Ukraine were increasing, which it said amounts to a violation of medical neutrality and international humanitarian law.

Ukrainian negotiators said a third round of talks with Russia on a ceasefire would go ahead tomorrow, although Moscow was less definitive.

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US Secretary of State Antony Blinken said the United States has seen very credible reports of deliberate attacks on civilians in Ukraine, adding that Washington was documenting them to support appropriate organisations in their potential war crimes investigation over Russia's actions.

Moscow calls its campaign a "special military operation", saying it has no plans to occupy Ukraine.

Ukrainian President Volodymyr Zelensky said Russian rockets had destroyed the civilian airport of the central-western region capital of Vinnytsia today.

Russian forces opened fire at a protest against their occupation of the southern Ukrainian city of Nova Kakhovka today, wounding five people, Ukrainian news agency Interfax said, citing eyewitnesses.

Kyiv renewed its appeal to the West to toughen sanctions,and also requested more weapons, including a plea for Russian-made planes, to help it repel Russian forces.

Speaking on NBC's "Meet the Press" show, Mr Blinken said the United States and European partners are exploring banning Russian oil imports, but stressed the importance of steady oil supplies globally.

The West has so far refrained from direct measures on Russian energy exports after oil soared to multi-year highs.

Ukraine's military said more than 11,000 Russian troops had been killed so far and 88 Russian aircraft shot down since the start of the invasion.

Reuters could not corroborate the claim. Russia has not given regular updates on its death toll.