Here are the latest developments in the war in Ukraine:

Ukrainian President Volodymyr Zelensky addresses the United Nations Security Council later on Tuesday for the first time since the invasion of his country.

It was not immediately clear if his speech would be recorded or live but it was expected to discuss the grisly discovery of hundreds of deaths in areas around Kyiv from which Moscow has withdrawn.

Zelensky has accused Moscow of war crimes and "genocide" and is seeking stronger international pressure on Russia.

Satellite images taken in mid-March and released by the firm Maxar Technologies appear to show bodies lying in the streets of Bucha, potentially rebutting claims by Russia that the deaths occurred after its withdrawal from the town.

Moscow has systematically denied responsibility for civilian deaths in the area, claiming images were "fakes" and that any killings came after Ukrainian forces entered Bucha.

US President Joe Biden calls for a war crimes trial and more sanctions on Russia over the deaths in Bucha, while European Commission chief Ursula von der Leyen says the EU is ready to send a team of investigators to gather evidence.

Global outrage grows over the discovery of dozens of bodies in the Ukrainian town of Bucha
Global outrage grows over the discovery of dozens of bodies in the Ukrainian town of Bucha AFP / RONALDO SCHEMIDT

Ukrainian authorities say they have found the bodies of five civilians with their hands tied in a village west of Kiev, including those of the mayor, her husband and son.

Police show AFP journalists four bodies, including that of the mayor, half buried in a grave in a pine forest bordering her house in Motyzhyn. A fifth body is located in a nearby well.

Ukrainian prosecutor general Iryna Venediktova says on Twitter that the bodies of five men tortured and killed by Russian troops have been found in the basement of a children's health resort in Bucha.

Kyiv's mayor Vitali Klitschko warns residents who fled the capital not to return for "at least another week", cautioning that explosives laid around the area are still a threat.

Some areas are also under curfew and he says he cannot "rule out the possibility of rocket fire".

Russian troops are preparing for a big attack in the Lugansk region of eastern Ukraine, the local governor Sergiy Gaiday says on Telegram.

Global outrage grows over the discovery of dozens of bodies in the Ukrainian town of Bucha
Global outrage grows over the discovery of dozens of bodies in the Ukrainian town of Bucha AFP / RONALDO SCHEMIDT

"We see that equipment is coming from different directions, they are bringing manpower, they are bringing fuel," he says, adding that Russia is "preparing for a full-scale big breakthrough".

A senior Pentagon official says Russia has removed about two-thirds of the troops it had around Kyiv, mostly sent back to Belarus with plans to redeploy elsewhere in Ukraine.

The White House warns the next phase of the war could last "months or longer".

The southeastern port city of Mariupol has been "90 percent" destroyed after being besieged by Russian forces, its mayor Vadym Boichenko says, adding 40 percent is "unrecoverable".

Around 130,000 people remain trapped in the city, which continues to be pounded by Russian bombardments, he says.

The Red Cross, which has tried and failed to evacuate people from the city, says a team sent to help get civilians out was being held by police in Russian-controlled territory.

The White House says more sanctions against Russia will be announced "this week", and the EU's foreign policy chief Josep Borrell says the bloc is urgently discussing further measures.

French President Emmanuel Macron says that they could target Russia's oil and coal sectors, while Germany warns that cutting off the supply of Russian gas to Europe is not yet possible, despite calls to do so.

The United States and Britain announce plans to seek Russia's suspension from the UN Human Rights Council over killings in Bucha.

Russia reacts furiously, deeming the bid "unbelievable" and "unprecedented".

Germany and France each expel dozens of Russian diplomats over the invasion.

And the former Soviet republic of Lithuania expels the Russian ambassador to Vilnius over what it calls the "horrific massacre" in Bucha and atrocities in other occupied Ukrainian cities. Moscow vows to retaliate.

More than 4.2 million Ukrainian refugees have fled the country since the Russian invasion, the UN says.