Russian troops have been battling for control of Severodonetsk in eastern Ukraine. Ukrainian authorities say more than 500 people are sheltering in a chemical plant there. Some fear the Russians will lay siege to the site as they did a steel factory in the port city of Mariupol.

Russians forces have destroyed bridges, effectively making it impossible for civilians to escape. However, defense officials in Moscow said they will open a humanitarian corridor. They also said Ukrainian fighters should stop their "senseless resistance" and surrender.

Ukrainian President Volodymyr Zelenskyy decried the bloodshed. He said the intense action in Severodonetsk and in surrounding areas has brought casualties, as before. He added that they are painful for all Ukrainians.

Zelenskyy again asked allies to provide his forces with modern anti-missile weapons. He says there are no good excuses for any delays.

On Wednesday, US Defense Secretary Lloyd Austin will chair a meeting of delegates from dozens of nations. He and other members of the Ukraine Defense Contact Group will discuss how they can help in the fight.