TRIPOLI, May 7 (Xinhua) -- Three children were killed and five other people wounded late Sunday when fresh tribal clashes erupted in the southern Libyan city of Sabha.

"The emergency department at 22:00 local time (2000 GMT) received the bodies of three children from one family, as well as five wounded people, including the children's parents, who are in serious condition," Sabha Medical Center said in a statement.

"Indiscriminate mortar shells fell on the houses of the victims, after renewed clashes broke out in the city," the statement said.

The medical center said 23 people have been killed and 91 others injured in tribal fightings over the past three months.

Sabha, some 800 km west of the capital Tripoli, has been suffering violent clashes between rival tribes since February, which have displaced more than 200 families.

A security source in the city told Xinhua that "many densely populated neighborhoods and government buildings were hit by indiscriminate shelling during the fighting."

"The neighborhoods of Al-Gal'a, Hajara, the airport, Sabha Medical Center, and Tayuri district are now in the range of clashes that occur almost every day," said the source, who declined to disclose his name.

The United Nations Support Mission in Libya has expressed concern on several occasions about the military escalation in Sabha, demanding indiscriminate use of weapons be stopped in densely populated areas.