The death toll from a drone strike on a student dorm in the Russian-controlled Luhansk region of eastern Ukraine has risen to 12, Russia’s state-run news agency RIA reported on Saturday citing the emergency ministry.

Russia on Friday accused Ukraine of what it described as a deliberate drone strike in the town of Starobilsk, with Russian President Vladimir Putin on Friday ordering his military to prepare options for retaliation.

The attack came after Russian President Vladimir Putin ordered retaliatory military action following a Ukrainian drone strike on a college dormitory in Starobilsk, a Russian-controlled area in the Luhansk region of Ukraine, which killed 11 people. Separately, Ukraine’s overnight drone attack on Russia triggered a fire at a Russian oil terminal. Russian authorities said, falling drone debris sparked the blaze and injured two people.