US Security Council spokesman John Kirby said that according to US estimates, more than 20,000 Russian soldiers had been killed and another 80,000 wounded in Ukraine since December.
Half of the 20,000 victims are from the Wagner mercenary company, which is fighting toward eastern Bakhmut.
Russian forces have captured most of Bakhmut, but Ukrainian troops still control a small western part of the city. The battle of Bakhmut has a tremendous symbolic significance for both sides.
