Tripoli, Libya (CNN) -- At least 15 people were killed and more than 40 wounded in battles between the Jihadist militant group Ansar al Sharia and forces loyal to a renegade general in the eastern Libyan city of Benghazi on Monday, according to hospitals in the city. Fighting erupted at about 2 a.m. when Ansar al Sharia fighters surrounded and attacked a Benghazi base belonging to a Libyan army special forces unit that allied itself with renegade Gen. Khalifa Haftar, according to residents and Col. Mohammed al-Hijazi, a spokesman for the self-declared Libyan National Army. Battles continued for hours in different parts of the city through the morning hours. Live pictures on the privately owned Libya al-Ahrar TV showed plumes of black smoke rising as explosions and gunfire could be heard in the distance.
@highlight
Ansar al Sharia fighters attack a base belonging to a Libyan army unit loyal to Gen. Khalifa Haftar
@highlight
Without Libyan government consent, Haftar is attacking Benghazi Islamist groups
@highlight
He says his Benghazi campaign is a war to purge Libya of extremist groups
@highlight
Jihadist group leader accuses him of war against Islam, warns U.S. not to back him
"We remain concerned about the safety of @placeholder residents who are caught in the armed clashes.
Libya ... will only show @placeholder what is more severe than what it saw there," he said.