The Ukrainian Security Forces has launched an air assault against pro-Russia separatists, after the rebels took control of Sergei Prokofiev International Airport in Donetsk.
Government forces sent in paratroopers, jets and a helicopter. Civilians and journalists were caught in the crossfire.
The pro-Russian rebels had hijacked the airport on 26 May, demanding the withdrawal of Ukrainian forces guarding the perimeter.
Kiev's anti-terrorist operation spokesperson Vladislav Seleznyov said that the military had requested that the unknown armed rebels surrender. However, the military launched an air strike after the gunmen did not comply.
All flights from and to the airport have been suspended.
Sergei Prokofiev International Airport spokesperson Dmitry Kosinov was quoted by the Daily Mail as saying: "The rebels are in the terminal. The rest of the airport area is controlled by the (Ukrainian) National Guard. The two sides are in talks now."
Russia, meanwhile, urged the Ukrainian Government to cease air strikes, describing them as a military operation against its own people.
The Russian Foreign Ministry said in a statement: "In connection with reports of armed clashes near Donetsk that have led to casualties, we urgently appeal to the leadership of the OSCE and its special monitoring mission in Ukraine to provide detailed information on the events there."
Ukraine's newly elected president Petro Poroshenko claimed that he would open talks with Moscow as early as June, in a bid to end a pro-Russia insurgency in the east.
Russian officials accepted Poroshenko's invite for talks, with Russian Foreign Minister Sergei Lavrov saying: "We, as our president said repeatedly, are ready for a dialogue with Kiev representatives, ready for a dialogue with Petro Poroshenko."
Image: Ukraine launches air strikes against pro-Russian rebels at Donetsk Airport. Photo: courtesy of Michael1238.