President Vladimir Putin said on Thursday that Russia had trapped the remaining Ukrainian soldiers in its western Kursk region, where they have clung on for more than seven months in one of the key battles of the war.

Kyiv has called on Moscow to respond to the proposed ceasefire - the Kremlin says it is waiting to be briefed by the US.

Why it matters: The U.S. and Ukraine both endorsed an unconditional 30-day ceasefire on Tuesday that calls for all air and artillery strikes to stop and fighting to cease all along the front lines. Putin raised doubts about that idea, and said any ceasefire should also be part of a process that addresses the "root causes of this crisis."