Ukraine's interior ministry says the military is now in full control of the airport in the eastern city of Donetsk after a day of bloody clashes.
More than 30 pro-Russia separatists were reported killed after an attempt to seize the airport early on Monday.
New President Petro Poroshenko vowed to tackle the eastern uprising in hours, not months. Russia has called for an immediate end to military action.
Meanwhile, the OSCE says it has lost contact with a monitoring team.