Thread by @fulelo

Ukraine news 🧵 on @bbcworldservice at 0700 AM GMT on 22.03 - listen live: bbc.co.uk/sounds/play/li…

President Biden has given his strongest warning yet that Russia may be preparing to use chemical and biological weapons in Ukraine. Mr Biden said President Putin "had his (cont.)

back to the wall" as a result of Ukrainian military resistance and the united response of the West -- and there was a danger he would resort to more severe tactics. He said false claims by Russia that Ukraine had chemical and biological weapons suggested it was

considering using both. Earlier, Moscow warned that relations with Washington were at "breaking point" after Mr Biden called Mr Putin a war criminal.

The Ukrainian President, Volodymyr Zelensky, has again called for direct talks with Vladimir Putin -- saying

it would not be possible to negotiate an end to the war unless they met. Mr Zelensky said he was ready to discuss all issues -- including the status of Russian- occupied Crimea and the Donbas, as well a security guarantees for Ukraine. But he said final decisions in these areas

would have to be put to the Ukrainian people in a referendum. On Monday, the Kremlin said not enough progress had been made in negotiations for direct talks between the two leaders.

The Ukrainian military say they have recaptured the town of Makaliv -- west of Kyiv -- after counter-attacking Russian forces. The military say there's been little movement on other fronts -- and the Russians appear to have stockpiles of fuel and ammunition for only three days.

But they say Russian air activity has increased over the past twenty four hours. The besieged southern port of Mariupol -- which has been devastated by weeks of bombardment -- is still the main focus of fighting.

The Ukrainian government says a futher 8000 people were evacuated from conflict zones on Monday. The deputy prime minister Iryna Vereshchuk said this included around three thousand people from the beseiged city of Mariupol, which has been under relentless Russian bombardment.

Around 300 000 civilians are still trapped there and efforts to deliver humanitarian aid have again been blocked. International journalists who visited Mariupol under Russian supervision have described an apocalyptic wasteland.

Ukraine has rejected Russian calls to surrender the city -- saying its defenders were preventing Russian forces from advancing elsewhere.

A Russian news outlet that briefly published what it said were official figures for the number of servicemen killed in Ukraine has said it was the victim of a hack. The article on the website of Komsomolskaya Pravda quoted the defence ministry as saying

nearly ten thousand Russians had been killed and more than sixteen thousand wounded. That's broadly in line with western intelligence assessments. The editor in chief told the BBC an explanation of what happened would be posted later.

The last official figure for the number of Russian dead -- published at the beginning of March -- put the number at just under five hundred