Russian Foreign Minister Sergei Lavrov and U.S. Secretary of State Marco Rubio discussed on Sunday prospects for settling the conflict in Ukraine and Russia-Ukraine talks set for Monday in Turkey, Lavrov's ministry said.

Kyiv also suffered a damaging blow when a Russian missile struck a Ukrainian military training base, killing at least 12 soldiers. Hours before that strike, Russia launched what Ukrainian officials said was the largest combined overnight aerial assault on the country since the start of the war.

While world leaders bicker over the prospects for peace, the deadliest conflict in Europe since World War Two is heating up fast.

By making harsh, uncompromising demands in peace talks with Ukraine while continuing to pummel it with waves of missiles and drones, Russian President Vladimir Putin is sending a clear message: He will only accept a settlement on his terms and will keep fighting until they're met.

Kyiv is hoping that being able to hit targets inside Russia will give it the strategic edge it has lacked until now.

The attack followed a night of bombardment, with Russia launching 472 drones, Ukraine’s air force said. Earlier Sunday, Ukraine’s army said a Russian missile strike on an army training unit killed at least 12 Ukrainian service members and injured 60.

The Russian economy faces a banking collapse, companies forgoing dividend payouts and a sharp downturn in growth.

Russia on Sunday claimed that it took control of another settlement in Ukraine's northeastern border region of Sumy. According to a Defense Ministry statement, Russian forces in the region captured the village of Oleksiivka, located about 5 kilometers (3.1 miles) from Ukraine's border with Russia.