Ukraine has carried out large-scale drone strikes against four airbases deep inside Russia, destroying multiple combat planes, according to a source in the Ukrainian Security Service (SBU).

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.

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.