A burnt truck is seen in the aftermath of clashes between pro-government forces backed by locals and the Benghazi Revolutionaries Shura Council who have joined forces with the Islamist militant group Ansar al-Sharia, in Benghazi last Saturday.

Reuters/Benghazi, Libya

Sitting in one of the last buildings still intact after months of fighting near Benghazi's airport, Libyan army special forces commander Wanis Bukhamada presides over a world of destruction.

His forces managed to stop an offensive of Islamist armed groups trying to take the airport in Benina, some 25 km south of the eastern city - just one battle in wider chaos gripping the major oil producer three years after the overthrow of Muammar Gaddafi.

"We've liberated Benina," Bukhamada said, working from a farm-turned-office equipped with a fax machine and Thuraya satellite phone.

The Benghazi clashes involving warplanes, tanks and artillery were among the worst since 2011. The violence has reinforced Western fears that Libya may be sliding into civil war as rival former rebel groups who helped topple Gaddafi use their heavy weaponry to carve out fiefdoms.

One armed faction with ties to the western city of Misrata took over the capital Tripoli after forcing out rival armed groups. It has since set up an alternative government, while the country's elected legislature and the internationally recognised administration is holed up in the eastern city of Tobruk.

The battle for Benghazi, Libya's second largest city, and its surroundings runs parallel to the Tripoli conflict. A chaotic struggle for control of the city after special forces were driven out has for months pitted government forces and irregular units against a coalition of Islamist brigades.

The regular army, like other Libyan institutions too weak to control rival armed factions, has now teamed up in Benghazi with forces of former general Khalifa Haftar, an ex-Gaddafi general who started his own campaign against Islamists in May.

But the rare victory of pro-government forces after an offensive launched last Wednesday comes at a heavy price. Benina looks like ghost town.

A Reuters reporter on a tour of the suburb organised by the army saw that almost all residential blocks, schools, a hospital and even a mosque were severely damaged or even destroyed.

More than 70 people have been killed in clashes since Wednesday.

Fighting was continuing on Tuesday in other parts of Benghazi, the cradle of the 2011 uprising that spiralled into a NATO-backed civil war against Gaddafi's one-man rule.

The Islamists have accused Egypt of carrying at air strikes in Benghazi to support Haftar, which Egyptian officials deny.

The US Government has said Cairo and the United Arab Emirates were behind strikes on Tripoli in August that failed to stop the seizure of the capital by the armed group from Misrata.

Libya's tiny and outdated airforce was badly damaged during the NATO-backed uprising in 2011.

In Benina, neglected like most cities in the east under Gaddafi as punishment for opposing his 42-year rule, street lights are upturned. The pot-holed roads are littered with shells from Grad rocket launchers, artillery and Kalashnikov guns.

While the army seemed to be in control of Benina on Tuesday, fighting inside Benghazi continued. Army backed by armed youth were clashing with Islamists inside the compound of Benghazi university and other places, residents said.