The clash came hours after Ukraine's acting president, Oleksandr Turchynov, had announced an "anti-terrorist operation" against the armed, pro-Russian insurgents who had seized control of numerous buildings in at least nine cities in Ukraine's restive east.
The central government has so far been unable to rein in the insurgents, who it says are being stirred up by paid operatives from Russia. The insurgents are demanding broader autonomy and closer ties with Russia, and complicating the political landscape, many local security forces have switched to their side.
The precise sequence of events in Kramatorsk was mired in confusion amid contradictory official claims.
Ukraine's security services anti-terrorist unit chief, Gen Vasyl Krutov, speaking outside Kramatorsk airport, said his men managed to thwart an attack by fighters in green military uniforms without insignia who tried to storm the facility in the late afternoon.
Also Read
An Associated Press reporter and camera crew at the airport heard rounds of gunfire at the time.
There were conflicting reports of casualties. Yury Zhadobin, coordinator of a pro-Russian defense force, said two people were slightly injured and were taken to a hospital.
Russia media, without sourcing, claimed anywhere from four to 11 casualties at the airport.
Ukraine government said there were no casualties and added that Ukrainian forces took an unspecified number of militiamen prisoner.
While he spoke of repelling an attack, the new government in Kiev declared that its forces had recaptured the airport from militiamen.