Ukraine crisis: Government forces in Sloviansk offensive
2 May 2014 Last updated at 14:57 BST
Pro-Russian rebels have shot down two of Ukraine's army helicopters during an "anti-terror" operation in the eastern city of Sloviansk, Kiev has said.
It said a pilot and serviceman had been killed, four suspected separatists held and 10 rebel checkpoints seized.
Half of the city was later declared "under control" of the Ukrainian units.
There has been no independent confirmation of the claim. Separatists at three checkpoints earlier told the BBC they were still in control there.
Sarah Rainsford reports from Donetsk in eastern Ukraine.