A Ukrainian security official said Saturday that one serviceman and one civilian have been killed in the past day as rebels in the east continue attacks despite a cease-fire declared three weeks ago.

Volodymyr Polyoviy, a spokesman for Ukraine's national security council said that the civilian died and 16 others were wounded in rebel mortar fire on the town of Shchastya, damaging the local hospital and a vocational school.

He also said one serviceman was killed and eight wounded over the past day, but did not give details. Rebel fire continued in the vicinity of the airport in Donetsk, the largest rebel-held city, he said. Ukrainian forces have held the airport against rebels since May.

More than 3,500 people have been killed in the conflict between Ukrainian forces and Russia-backed rebels.

Ukrainian forces' withdrawal from the Donetsk airport was among the issues discussed at a Friday meeting between representatives of Ukraine, the rebels, Russia and the Organization for Security and Cooperation in Europe, Russian state television reported.

Polyoviy confirmed that the meeting took place, but did not give details and said its results weren't known.

The OSCE has steered the peace process that resulted in the Sept. 5 cease-fire and a subsequent agreement under which both sides are to pull back heavy weapons in order to create a buffer zone.

Russia denies claims by Ukraine and Western countries that it has sent troops and equipment into Ukrainian territory to back the rebels.

Ukraine: 2 Killed in Clashes Despite Cease-Fire