WADI DINAR, Libya — Progovernment militias battled fighters in a former stronghold of the late Libyan dictator Moammar Khadafy on Sunday, the fifth straight day of clashes that have killed at least 30 people.

The fighting in Bani Walid, some 190 miles southeast of Tripoli, has overlapped with the anniversary of Khadafy’s capture and killing on Oct. 20, 2011. A year since his death brought an end to Libya’s civil war, Bani Walid is the most significant city in the country to still resist the nation’s new authorities.