Ukrainian troops have recaptured almost all the territory of Donetsk airport in eastern Ukraine.
They had lost the territory to separatists in recent weeks, even as thousands gathered in Kiev for a state-sponsored peace march.
Ukrainian troops launched a "mass operation" overnight at Donetsk airport, with a military spokesman saying they had retaken almost all the territory lost to separatists in recent weeks.
The army's offensive at the airport brought the fighting close to the city of Donetsk itself, the 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," said spokesman Andriy Lysenko.
Mr Lysenko said the operation had returned the battle lines near the airport to the previous status quo.
He said 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.
They have seized parts of the airport from government troops, which is of strategic value to both sides.
The World Health Organisation has said more than 4,800 people have been killed in the conflict.