At least seven people have been killed and 40 others wounded after assailants attacked an army base in the eastern Libyan city of Benghazi, residents and security sources say.
Monday's violence at the army base came after a week of fighting between rival groups for control of Tripoli International Airport that has prompted an appeal for international help to stop Libya from becoming a failed state.
"Ansar al-Sharia tried to take over one special forces camp, but the special forces and [Khalifa] Haftar's forces fought back, using helicopters and military aircraft in their attack," one source said on Monday, asking not to be identified for security reasons.
Khalifa Haftar, a former army general who fled to the US after breaking ranks with the Libyan leader Muammar Gaddafi, has launched a campaign against the Ansar al-Sharia in Benghazi, bringing to his side elements of the regular army and air force.
Since the 2011 civil war that toppled Gaddafi, Libya's fragile government and new army have been unable to assert authority over rival brigades of former rebels fighting for political and economic influence.
Ansar al-Sharia is listed by the US as a foreign terrorist organisation and has entrenched itself in Benghazi. The group has often been blamed for assassinations and attacks on soldiers.
Tripoli's central government says he is acting without the authorisation of the state. While his campaign is popular with many in the east, his forces appear to be in a stalemate over Benghazi for now.
In Tripoli, the clashes over control of the airport over the last week has killed at least 47 people, the Health Ministry said on Sunday.
The clashes have stopped most international flights, damaged more than a dozen planes parked at the airport and prompted the UN to pull its staff out of the country due to security concerns.
The airport battle mirrors a broader standoff between rival factions competing for power in Libya, each claiming the mantle of rebel saviour, each heavily armed and each demanding their share of the post-Gaddafi spoils.
The airport area is under the control of former fighters from the western town of Zintan who have held it since the fall of Tripoli in 2011.
Rival rebel groups allied with powerful brigades from the city of Misrata have fought with the Zintanis to dislodge them from the airport.
Three years since Gaddafi's death, the violence and militia rivalries have all but stopped the OPEC country's transition to full democracy as the government struggles to stamp its authority on a country where the state holds little sway.