TRIPOLI, Sept 3 (Reuters) – Fighting broke out in Tripoli early on Friday between rival armed forces, the heaviest clashes in the Libyan capital since the conflict between eastern and western factions paused a year ago. The new fighting pitted the 444 Brigade against the Stabilization Support Force, two of the main forces in Tripoli, a witness said. The United Nations Libya mission called for an immediate halt in the fighting, saying it had “grave concern”. Political factions have squabbled repeatedly over the role and powers of the interim government as well as over the control of state institutions and the public purse. Reporting by Ahmed Elumami in Tripoli and Hani Amara in Istanbul, writing by Angus McDowall, editing by Mark Heinrich, William MacleanIMAGE: Smoke rises after an attack on the Administrative Control Authority in Tripoli, Libya, August 31, 2021.