Fierce fighting in eastern Libya involving troops loyal to a former general who defected from the government to fight rebels has killed at least 12 people and injured 90, according to officials.
The country's top military official described an offensive on Friday — launched against insurgents without government approval — as a "coup," The Associated Press reported.
Military aircraft and helicopters, apparently under the command of Maj. Gen. Khalifa Haftar, flew over the city of Benghazi on Friday, Libyan security officials said.
Friday's assault marks the first time that army units have fought unilaterally and joined forces with Haftar, who once headed the army under Muammar Gaddafi but defected in the 1980s. After Gaddafi's ouster, he was assigned to help rebuild the forces but was removed by the government soon after.
In February, Haftar appeared in an online video that aired on several Libyan television stations. Wearing a military uniform, he stood in front of a map of Libya and the national flag and claimed to speak for the "general command of the Libyan army."
In the video, he said the military intended to "rescue" the nation.
Libya's government viewed Haftar's statement as a coup attempt. Later Libyan media reports claimed Haftar held meetings at air bases in eastern Libya to win the support of the military.
On the ground on Friday, Haftar's troops attacked the bases of the anti-government group Rafallah al-Sahati and another group known as Feb. 17, the officials said.
Maj. Gen. Abdel-Salam Gadallah al-Obeidi, Libya's chief of staff, said forces that launched the Benghazi assault were under Haftar's control. He did not, however, address claims that federal forces fought on Haftar's side.
Al-Obeidi said he would ban any forces from entering Benghazi to join Haftar.
Interim Prime Minister Abdullah al-Thinni later said only one jet moved out to attack the militias without government permission, along with some 120 weapons-loaded army vehicles.
"This is an attempt to use the current security situation to stand against the revolution ... The era of coup is gone,'' he said in a televised statement.
Libya's state LANA news agency, citing medical sources, said 12 people had been killed and 90 injured.
Mohammed al-Hegazi, a spokesman for Haftar, told the Libyan television station Al-Ahrar that some military units joined Haftar and his forces in their fight against the armed groups.
He said the operation, called the Dignity of Libya, included air forces and special forces.
Al-Hegazi said Haftar's forces now controlled two militia bases.
The "clashes will not stop until the operation achieves its goals," al-Hegazi said. He said forces based at the city's airport had also joined Haftar.
Associated Press footage from Benghazi showed at least one military helicopter flying overhead as gunfire crackled in the city.
Armed groups have grown in number and power after the ouster of longtime dictator Gaddafi in 2011, taking advantage of Libya's disarrayed military and police.
Also on Friday, Algerian's Foreign Ministry announced the closure of its embassy in Tripoli, citing "information of a clear and imminent threat" to its diplomatic personnel. The clashes also closed the Benghazi airport.
The statement did not specify if the ambassador and his staff had been evacuated and described the closure as a temporary measure in light of the "difficult security conditions."
Al Jazeera and wire services