US Secretary of State Antony Blinken said Monday that Ukraine's position in Russia's Kursk was critical to any future negotiations, as Moscow said Kyiv launched a counterattack in the border region, AFP reports.

"Their [i.e. the Ukrainian armed forces] position in Kursk is an important one because certainly it's something that would factor in any negotiation that may come about in the coming year," Blinken told reporters in Seoul.

Blinken said that even if negotiations take place, Ukraine would still need "adequate security assurances" against Russian President Vladimir Putin.

"There is going to be, at some point, a ceasefire. It's not going to be in Putin's mind 'game over,'" Blinken said.