Photo of Donetsk International Airport controlled by Ukrainian forces but still surrounded by pro-Russia militants.(Agence France-Presse)

Ukrainian forces and pro-Russian rebels were battling around the airport near the insurgent stronghold of Donetsk on Tuesday, sending flames and clouds of black smoke into the sky, AFP journalists said.The fighting erupted despite a new truce agreement reached on Saturday which calls for forces on both sides to cease fire and pull back from the frontline to create a buffer zone.

The airport, which was severely damaged in a fierce battle in May, was hit by heavy artillery and the rattle of automatic weapons fire could also be heard, the journalists said.Donetsk is the largest insurgent-held city in the conflict zone in eastern Ukraine but the airport remains under the control of government forces despite numerous rebel assaults.