Russia's foreign minister is sharply criticizing Ukraine's insistence that it won't begin pulling back heavy weapons in its fight against separatists in the east until the rebels fully observe a cease-fire.

Sergey Lavrov told a news conference that the stand is "ridiculous."

"Everyone understands that there isn't an ideal truce and an ideal regime of ceasing fire," he said.

Ukrainian military spokesman Lt. Col. Anatoliy Stelmakh on Thursday said cease-fire violations during the night were relatively few, but included shelling the village of Pisky on the outskirts of Donetsk, the largest rebel-held city.

He reiterated that Ukrainian forces would not begin the weapons pullback envisioned under a peace accord until attacks have ceased. The rebels claimed Tuesday to have begun their pullback, but that has not been independently confirmed.