Libyan jets attack
A member of the February 17th Brigade, points at the site of a bombing at the brigade's base after it was bombed by two jets in Benghazi May 28, 2014. CReuters/Esam Omran Al-Fetori

(Reuters) - Libyan warplanes bombed militia bases in Benghazi on Wednesday as part of a renegade former general's campaign to purge the chaotic North African state of Islamist militants, witnesses and officials said.

Two jets attacked a base belonging to the February 17 brigade, one of the Islamist-leaning armed groups operating in Benghazi, and an Ansar al-Sharia militant base in the west of the city, a Reuters witness and an air force official said.

The attacks are part of a campaign by irregular forces loyal to former Libyan army general Khalifa Haftar who earlier this month launched operations against Islamist militants he says the weak central government has failed to control.

"Our forces are bombing the February 17 battalion base and Ansar al-Sharia base in Quarsha," Mohamed Hejazi, a spokesman for Haftar, told Reuters.

There were no immediate reports of casualties from local hospitals. A Reuters witness at the February 17 base said there were no casualties and only structural damage.

Benghazi's Benina air base is one of the regular units which joined Haftar's campaign. But rival militia brigades and political factions have rejected his operation as an attempted coup, after forces loyal to him also attacked parliament a week ago.

Libya's Ansar al-Sharia militant group, listed as a terrorist group by Washington, on Tuesday warned the United States against interfering in the country's crisis and accused the U.S. government of backing Haftar.

The OPEC oil producer is in turmoil three years after the NATO-backed war that ousted Muammar Gaddafi, with Islamist, anti-Islamist, regional and political factions locked in conflict over its future. Gaddafi's authoritarian rule and three years of unrest have left Libya with few institutions and no real national army to impose state authority on the competing militias and brigades of former rebels who have become power-brokers.