US Says Ukraine Has Taken Back 50% Of Territory That Russia Seized

"These are still relatively early days of the counteroffensive. It is tough," he said, adding: "It will not play out over the next week or two. We're still looking I think at several months."

Secretary of State Antony Blinken said that while Ukraine has reconquered half the territory that Russia initially seized in its invasion, Kyiv faced a "a very hard fight" to win back more.

"It's already taken back about 50% of what was initially seized," he said in an interview to CNN on Sunday.

"These are still relatively early days of the counteroffensive. It is tough," he said, adding: "It will not play out over the next week or two. We're still looking I think at several months."