After clinging for more than seven months to a gradually shrinking area, Ukraine has seen its position worsen sharply in the past week.

Russian President Vladimir Putin has called on Ukrainian troops in the Russian region of Kursk to surrender, as diplomatic back-and-forth continues over a potential US-brokered ceasefire with Ukraine.

The Kremlin said there are reasons to be optimistic about a settlement to the conflict but that more work needs to be done.