Hardline Islamist groups in Libya are claiming a major victory after seizing a special forces base in the eastern city of Benghazi, following a battle involving rockets and military jets that killed at least 30 combatants.

Saiqa, the special forces unit that previously occupied the base, is widely respected as the best trained and most effective division in the Libyan military, but a sustained attack forced it to evacuate its Bu Attni base on 29 July, leaving it in the hands of militias allied with radical Islamist group Ansar al-Sharia.

Saiqa and several air force units have teamed up with former major general Khalifa Haftar, who has been waging war with country’s Islamist militias over the past three months without the central government’s approval.

Ansar al-Sharia branded Haftar an “agent for the west” and a “war criminal” in a propaganda video released on the same day that its militants seized the special forces base.

The victory for the Islamists in Benghazi comes as a fierce turf war continues in Tripoli, the country’s capital, causing foreign diplomats to leave the city.

The US withdrew from the country on 26 July and was quickly followed by Canada and Italy. A convoy of vehicles evacuating non-essential staff from the British embassy came under heavy fire on Sunday 27 July, but no one was hurt.

More than 150 people have been killed in fighting in Benghazi and Tripoli over the past two weeks.