More from Reuters on the biggest story of the weekend:
Ukrainian troops launched a "mass operation" overnight retaking almost all the territory of Donetsk airport in eastern Ukraine lost to separatists in recent weeks, military spokesman Andriy Lysenko said on Sunday.
The army's offensive at the airport brought the fighting close to the city of Donetsk itself, centre of a pro-Russian separatist rebellion. Residents reported intensified outgoing shelling including from residential areas in central parts of the separatist-held city.
"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," Lysenko said in a televised briefing.
Lysenko said the operation had returned the battle lines near the airport to the previous status quo and that the Ukrainian army had thus not violated the Minsk 12-point peace plan agreed with Russia and separatist leaders last September.
Four Ukrainian soldiers had been killed and 32 injured in the past 24 hours, he said.
With attempts to restart peace talks stalled, pro-Russian rebels have stepped up attacks in the past week, seizing from government troops parts of the airport, which is of strategic value to both sides.