Ukraine war: Zelenskyy decries 'outright terror' of Russia stranglehold on Mariupol

Volodymyr Zelenskyy has described Russia's refusal to allow evacuations from Mariupol as "outright terror". Conditions in the southern seaport of 430,000 are increasingly dire as trapped civilians scrounge for food and fuel.

There are signs of a Russian advance towards Kyiv. Satellite photos appear to show that a massive convoy until now stationary outside the Ukrainian capital has split up and fanned out into towns and forests, with artillery pieces moved into firing positions.

Washington and Kyiv have derided unsubstantiated Russian claims that the US is developing biological weapons in Ukrainian territory. They fear Moscow is paving the way for its own use of non-conventional weapons in Ukraine. The UN Security Council has scheduled a meeting for Friday at Russia’s request.

Follow the latest developments in our live blog below on the war in Ukraine.

The UN Security Council will meet on Friday to discuss Russia's claims that the United States is conducting “military biological activities" in Ukraine.

White House press secretary Jen Psaki Psaki called the claim “preposterous.”

“This is all an obvious ploy by Russia to try to justify its further premeditated, unprovoked, and unjustified attack on Ukraine,” Psaki tweeted.

Ukraine's President Zelenskyy said the accusation itself is a bad sign.

“That worries me very much because we have often been convinced that if you want to know Russia’s plans, they are what Russia accuses others of,” he said in his nightly address to the nation.

"What does it mean, that we're being accused of preparing chemical attacks? Have you decided to conduct a dechemicalisation of Ukraine? With what? With ammonia? With phosphorus? What else have you prepared for us?"

"What do you plan to hit with chemical