A retired Libyan general prepared 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.

A retired Libyan general prepared 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.

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.

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 79 people.

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.

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

Haftar says his campaign against the Islamists aims 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 Moammar Gaddafi, has denied any involvement in the Benghazi clashes.