US 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," Blinken 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."
Hopes that Ukraine could quickly clear Moscow's forces from its territory following the launch of a summer counteroffensive are fading as Kyiv's troops struggle to breach heavily entrenched Russian positions in the country's south and east.
Late last month President Volodymyr Zelenskiy was quoted as saying that progress against Russian forces was "slower than desired" but that Kyiv would not be pressured into speeding it up.
