Forces loyal to Libya's internationally recognized government have been fighting Islamist groups in the country's second-largest city for over a year, part of a wider struggle since Muammar Gaddafi was overthrown and killed in 2011.

Army forces backed by armed residents have regained some of the territory in Benghazi lost last year. But critics say their air strikes and artillery have pounded parts of Benghazi into rubble without gaining much ground.

New clashes erupted on Wednesday in the Lithi district, a stronghold of militant Islamists. During the fighting, Salem al-Naili, the commander of a special forces brigade, and another soldier were killed, army officials said. Four more soldiers were wounded.

Islamic State, which has expanded in Libya by exploiting a vacuum as two governments vie for control, claimed responsibility on social media for Naili's killing.

Islamic State and other militant groups have been getting support from groups in Tunisia, Algeria, Chad, Nigeria and Sudan, a top army commander told reporters after meeting with senior commanders in Marj town east of Benghazi.

Asked when the Benghazi battle would be finished, the commander, Khalifa Haftar, said: "I cannot give a date but it will be very soon."

U.N. Special Envoy Bernardino Leon disputed that. "In Benghazi, clashes ... continue with neither side making significant gains," he told the U.N Security Council.

The fighting for Benghazi highlights the chaos in Libya, where armed groups back two governments vying for control. The official prime minister has been based in the east since the capital, Tripoli, was seized by a rival group which set up its own government.

Both sides command loose coalitions of former anti-Gaddafi rebels. After Gaddafi's ouster, the various factions split along political, regional and tribal lines.

Islamic State has exploited the chaos by taking over several towns, executing foreigners and launching attacks against embassies in Tripoli.

--reuters--