(Recasts with defence ministry statement)
KRAMATORSK, Ukraine, April 25 (Reuters) - A Ukrainian military helicopter was hit by rocket fire and exploded while on the ground on Friday at an airfield near the rebel-held eastern city of Slaviansk, the Defence Ministry said.
"According to a preliminary assessment, the explosion was the result of fire from a rocket-propelled grenade launcher," it said in a statement. There were no casualties, it said.
A senior security official earlier told a news briefing that the Mi-8 transport helicopter was hit in the fuel tank by a sniper bullet and that the pilot was injured.
A Reuters correspondent saw thick black smoke rising over the airfield and Ukrainian troops were barring access. Local residents said they had heard shooting and three explosions. (Reporting by Thomas Grove in Kramatorsk, Ukraine and Sergei Karazy, Pavel Polityuk and Alastair Macdonald in Kiev; Writing by Alastair Macdonald; Editing by Sonya Hepinstall)