Thousands of civilians are reportedly trapped in the Ukrainian city of Severodonetsk with a inadequate water supply.
It says an urgent situation is developing in the bunkers beneath the Azot chemical plant where hundreds of civilians are taking shelter in the key eastern city.
The US has pledged another $1bn of weapons aid to Ukraine, President Joe Biden says.
The Russians have lost roughly 20-30% of their armoured force during the war in Ukraine, US General Mark Milley says.
Nato has said the spike in global food prices is a direct consequence of the war and not sanctions against Russia as being claimed by Moscow.
Nato chief Jens Stoltenberg also said the alliance will continue to supply Ukraine with heavy weapons