Jihadist group Ansar al-Sharia has attacked Libyan special forces in the eastern city of Benghazi, sparking a battle in which nine people were killed and dozens wounded.
Military governor Colonel Abdullah al-Saidi on Monday declared a "state of alert" and ordered all soldiers to report for duty at their barracks, in what was the first such confrontation between the army and Libya's heavily-armed top jihadist group.
As the government warned the army was a "red line" not to be crossed, Interior Minister Seddik Abdelkarim announced in Tripoli a casualty toll of nine dead and 49 wounded.
Medics in Benghazi's Al-Jala hospital earlier reported five soldiers killed and 29 people wounded, including 10 civilians.
The number of casualties on the jihadists' side was not immediately known as they were being treated in a clinic run by Ansar al-Islam.
"A violent clash has been taking place for several hours between our forces and an Ansar al-Sharia cell," Colonel Milud al-Zwei, spokesman for Libya's special forces, told AFP.
According to Zwei, the fighting broke out after a special forces patrol near the group's headquarters came under attack.
"The army retaliated, sparking clashes with all types of weapons," he said.
The spokesman said fighting between the two sides spread to other districts of Benghazi, especially near the group's charity clinic in the Selmani area.
Explosions and gunfire could be heard in several neighbourhoods, an AFP journalist said.
Witnesses said gunmen had set up checkpoints on roads leading into Benghazi to prevent reinforcements reaching the Islamists.
But a relative calm was restored in the early afternoon.
Ansar Al-Sharia emerged after the 2011 fall of Moamer Kadhafi's regime, with its military wing composed of former rebel fighters.
Blamed for the murders of judges and security personnel in Benghazi, it is also suspected of responsibility for a September 2012 attack in which the US ambassador and three other Americans were killed.
It denies any involvement.
Ansar al-Sharia, which demands implementation of sharia Islamic laws as the sole source of legislation, controls areas of Benghazi as well as Sirte and Derna, also in eastern Libya.
