General Christopher Donahue, commander of U.S. Army Europe and Africa, said allies could seize Kaliningrad "in a timeframe that is unheard of."

The Russian invasion of Ukraine has had a profoundly negative impact on Ukraine, as well as on the global food, financial, and energy markets.

Trump continues to assure his allies that negotiations remain on track, the official said. However, according to another source, there is growing recognition that the talks — which Trump had publicly predicted would culminate in a trilateral summit within a week — are progressing slowly and “with difficulty.