President Volodymyr Zelenskyy of Ukraine said Russian forces were throwing "everything they can” at Kyiv’s troops fighting to retake land in the south and east, again emphasizing the grueling nature of a counteroffensive that is moving more slowly than some allies had hoped and later stressing the importance of their continued support.

Ukrainian troops have made only small gains since launching the widely anticipated campaign in June, and in recent weeks, they appear to have stalled in some areas in the face of staunch Russian defenses. Casualties are mounting, and U.S. officials have said Ukraine has also lost newly provided Western armored vehicles in field after field of land mines.

Zelenskyy, who has defended the pace of the counteroffensive, said in his nightly address late Friday that he had had a "detailed” meeting earlier in the day with his top commanders to discuss the front lines and "logistics” — including weapons and the "rational use of shells, supplies from partners,” an apparent reference to the rate at which Ukraine’s forces are expending ammunition.