TRIPOLI, April 23 (Xinhua) -- Clashes between an army unit and tribal gunmen in the southern Libyan city of Sabha on Monday killed two people and wounded five others, a medical source said.

"The center on Monday has received two dead bodies and five wounded people, as a result of the clashes," a source of Sabha medical center told Xinhua.

Mohammad al-Tabawi, a leader of the Tabu tribe, said an army unit fired motor shells on a Tabu-populated district, causing the casualties.

"The clashes renewed after a one-day standoff, when the army's 6th Brigade fired mortar shells at Toyuri district. We fired back at the source of the shelling," al-Tabawi told Xinhua.

One civilian was killed and two others were injured on Saturday when tribal clashes erupted in Sabha, according to military and medical sources.

Sabha has been witnessing heavy clashes between rival tribes since February, which killed and injured dozens of people and displaced more than 200 families from their homes, according to a medical report.

The United Nations Support Mission in Libya expressed concern over several occasions about the military escalation in Sabha, demanding to stop indiscriminate use of weapons in densely populated areas.