KIEV: Ukrainian troops launched a “mass operation” overnight, retaking almost all the territory of Donetsk airport in eastern Ukraine lost to separatists in recent weeks, even as thousands gathered in Kiev for a state-sponsored peace march on Sunday. The army’s offensive at the airport brought the fighting close to the big industrial city of Donetsk itself, center of a pro-Russian separatist rebellion.

Residents reported intensified outgoing shelling including from residential areas in central parts of the separatist-held city.

With attempts to restart peace talks stalled, pro-Russian rebels have stepped up attacks in the past week and casualties have mounted, including the deaths of 13 civilians in an attack on a passenger bus, which Kiev has blamed on the separatists. The separatists had gained control of new areas of the airport and retaking much of this territory was a symbolic victory for Kiev, whom rebels have accused of escalating the conflict.

“The decision was taken for a mass operation ... We succeeded in almost completely cleaning the territory of the airport, which belongs to the territory of Ukrainian forces as marked by military separation lines,” military spokesman Andriy Lysenko said in a televised briefing.