Retired U.S. military leaders reacted on Sunday after Ukraine carried out a large-scale drone attack on Russian military aircraft deep inside the country, with one quipping that Russian President Vladimir Putin is "having a very bad day.

Russian President Vladimir Putin signed a decree that forces Ukrainians to legalize their status in occupied territories — or leave. Already, many Ukrainians had been forced to accept Russian citizenship in occupied areas to maintain their homes or access to health care and education.

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.

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.

At least seven people were killed after Russian officials said “illegal interference” caused a bridge to collapse and a train to derail in Russia.

A bipartisan pair of US senators met with Ukrainian President Volodymyr Zelensky in Kyiv on Friday and urged stronger sanctions against Russia, while uncertainty swirls over whether the next round of peace talks will move ahead in the coming days.

A Ukraine presidential adviser says Ukraine is ready to resume direct peace talks with Russia in Istanbul on Monday but insists that the Kremlin provide a promised memorandum setting out its position on ending the war.