Ukraine pleads for more weapons as battle rages for beseiged city of Mariupol

Ukraine pleaded for more weapons from the West to help it end the siege of Mariupol and fend off an expected Russian offensive in the east, as more reports emerged of rape and brutality against Ukrainian civilians by Russian forces.

Ukrainian President Volodymyr Zelensky said in a televised address late on Monday that Russia could resort to chemical weapons as it amassed troops in the eastern Donbas region for a new assault on the port of Mariupol, where thousands are believed to have died under a near-seven week siege.

"When it comes on the necessary weapons, we still depend on supplies, on our partners. Unfortunately we are not getting as much as we need to end this war faster ... in particular, to lift the blockade of Mariupol," he said.

The first European Union leader to meet Russian President Vladimir Putin in person since he launched what he called a "special operation," Austrian Chancellor Karl Nehammer, said following talks in Moscow on Monday that an offensive in the east was "being prepared on a massive scale."

After suffering heavy losses and withdrawing forces from the suburbs of Kyiv, Russia has turned its sights toward Donbas, where it demands Ukraine cede control to separatist fighters. Capturing Mariupol would allow Moscow to attempt to encircle the main Ukrainian force in the east.

Delivering a regular early morning roundup from the conflict zone, the General Staff of Ukraine's Armed Forces said that aside from trying to take control of Mariupol, Russian forces were also intent on capturing Popasna, a town more than two hours' drive west of Luhansk, and were set to launch an offensive in the direction of Kurakhove, in the Donetsk region.

The Ukrainian military said its troops had repulsed attacks in both the Luhansk and Donetsk regions, destroying four tanks, five armoured vehicles, 26 vehicles and eight enemy artillery systems. It also said its forces had downed a Russian plane, two helicopters and four drones. Reuters could not independently verify those figures.

Serhiy Gaidai, the governor of Luhansk, urged residents to evacuate using five humanitarian corridors agreed for the Eastern Ukrainian region on Tuesday.

"It's far more scary to remain and burn in your sleep from a Russian shell," he wrote on the Telegram messaging app. "Evacuate, with every day the situation is getting worse. Take your essential items and head to the pickup point."

In all, nine humanitarian corridors had been agreed for Tuesday, including one for private cars from Mariupol, Ukraine's Deputy Prime Minister Iryna Vereshchuk said.

British Foreign Minister Liz Truss on Monday said Britain was working with its partners to verify the details of reports Russian forces may have used chemical agents in an attack on Mariupol.

"There are some things that are beyond the pale, and the use of chemical weapons will get a response and all options are on the table for what that response could be," Britain's Junior Defence Minister James Heappey told Sky News.

The departure of Russian forces from the outskirts of Kyiv has brought to light harrowing allegations of war crimes including executions and rape of civilians. Moscow dismisses the allegations as Ukrainian and Western provocations and has also accused Ukrainian forces of sexual violence.

Senior UN official Sima Bahous told the Security Council on Monday that while all allegations must by independently investigated, "the brutality displayed against Ukrainian civilians has raised all red flags."