BENGHAZI, Rajab 17, 1435, May 16, 2014, SPA -- Libyan irregular forces backed by helicopters clashed with Islamist militias in Benghazi on Friday in fighting that left at least four people dead and posed a new test to the country's fragile government. Irregulars of the self-declared Libyan National Army, led by retired General Khalifa Haftar, shelled bases belonging to Ansar al-Sharia and another Islamist militant group in Benghazi, said Mohamed Al-Hejazi, a spokesman for Haftar's forces, according to Reuters. The violence prompted Libya's prime minister to order the regular military to control any armed groups - including Haftar's forces - in the eastern city, where militants often clash with the army, and assassinations and bombings are common. Benghazi, the cradle of the NATO-backed uprising against Gaddafi, in particular has struggled to curb violence and stem attacks blamed on Ansar al-Sharia, which often operates openly despite being designated a terrorist organisation by Washington. Libya's army chief of staff told state television he had given no orders for any regular military units to attack bases in Benghazi. Hours later, Prime Minister Abdullah al-Thinni told reporters: "We have given orders ... to intercept any force trying to enter Benghazi because they don't have legitimacy from the state." The city was calmer in the afternoon after the clashes in the morning, when witnesses said at least one regular army helicopter had been used in some of the assaults on the Islamist bases. At least four people were killed and another 30 injured in the fighting, medical sources at a local hospital said. -- SPA 18:53 LOCAL TIME 15:53 GMT www.spa.gov.sa/1233174