Separatist rebels in eastern Ukraine have accused government forces of shelling residential areas under their control with heavy artillery.

The uptick in fighting, reported by both side in the past few days, comes as the foreign ministers of Russia, Ukraine, France and Germany are gathering Friday for talks to discuss a peace settlement for the conflict which has already claimed more than 8,000 lives.

The rebel mouthpiece Donetsk News Agency said on Friday that Ukrainian forces used Grad multiple rocket launchers Thursday night and Friday morning north of Donetsk.

Ukrainian forces also accused the rebels of violating the ongoing cease-fire.

The Sept. 1 cease-fire has largely held with both sides pulling back weaponry from their positions. Heavy weaponry was supposed to have been withdrawn weeks ago.