A retired Libyan general was preparing on Sunday to renew an offensive against Islamist former rebels in the eastern city of Benghazi, after being accused by the authorities of an attempted coup.

Major General Khalifa Haftar appeared determined to pursue his campaign after saying late on Saturday that his withdrawal from the city the day before was so his forces could regroup before attacking again.

Haftar has been using government aircraft and troops in an unauthorised campaign against Islamist groups.

Overnight, an explosion hit the offices of a radio channel run by the Ansar al-Sharia group, the main target of attacks on Friday by Haftar's self-described "National Army" that killed at least 70 people and injured 140, medical sources told Al Jazeera.

There were no reports of casualties in the blast, witnesses said.

They said armed men aboard a vehicle had thrown an explosive device at the building before speeding off. No group has claimed responsibility for the attack.

The radio station's offices are in central Benghazi's Al-Lithi district, an Islamist stronghold.

Ansar al-Sharia, which the United States has designated as a "terrorist" organisation, has been blamed for a wave of attacks on security forces and Western interests in Libya's second largest city.

Coup attempt 'denied'

Haftar says his campaign against the Islamists aimed to purge the restive city of "terrorist" groups, but he has been denounced by the authorities in Tripoli of trying to stage a coup - a charge he denies.

The North African nation's regular army, still not properly operational nearly three years after the uprising that toppled Muammar Gaddafi has denied any involvement in the Benghazi clashes.

On Saturday the Libyan army imposed a no fly zone over Benghazi in a direct challenge to Haftar.

Interim Prime Minister Abdullah al-Thinni also denounced Haftar's forces as "outlaws" and called on all parties to observe restraint.

Haftar lived in exile in the United States for nearly two decades before returning home to lead ground forces in the 2011 NATO-backed uprising that toppled Muammar Gaddafi.

Source: AFP