Ukrainian warplanes and artillery continue to pound the cities of Luhansk and Donetsk, the last strongholds of eastern secessionist rebels, and the military claimed to have taken over a large part of Luhansk in a ground operations.

The death tolls are mounting, mostly from the shelling, and 43 civilians were confirmed killed in Donetsk from the intense attacks by Ukrainian artillery. 52 were reported slain overall, including combatants in the gun battles.

Ukraine also lost another warplane in the course of today’s bombings in Luhansk. This time, it was a Su-25 that was shot down, though details remain scant on the fate of the pilot. It is the second plane lost this week, after a MiG-29 was shot down Monday.

Donetsk remains firmly in the hands of the rebels, though surrounded by Ukrainian military forces and under constant shelling. The humanitarian crisis the siege has caused has displaced about one million civilians, mostly into neighboring Russia. Russia is trying to send humanitarian aid to Donetsk, though it is stuck in customs at the border, with Ukraine complaining the aid shipments amount to an “invasion.”

The secessionist rebels are predominantly ethnic Russians, and are seeking either to break off from Ukraine or gain considerable autonomy. Russia has been backing them and trying to negotiate a settlement, so far without success.