Forces under Libya's UN-backed government said Sunday they had started a counter-attack against the forces of Khalifa Hifter after he launched an offensive to seize Tripoli, escalating an ongoing power struggle in the oil-rich country.
"The Armed Forces announce the launch of Operation Volcano of Anger to cleanse all Libyan cities from aggressors and illegitimate forces," spokesman Mohamed Ganounou of the UN-backed government's forces said in a statement.
A top military official said Sunday that the United States temporarily withdrew some of its forces from Libya due to "security conditions on the ground," as a Libyan commander's forces advanced toward the capital of Tripoli and clashed with rival militias.
A small contingent of American troops has been in Libya in recent years, helping local forces combat Islamic State and al-Qaida militants, as well as protecting diplomatic facilities.
"The security realities on the ground in Libya are growing increasingly complex and unpredictable," said Marine Corps Gen. Thomas Waldhauser, the head of U.S. Africa Command. "Even with an adjustment of the force, we will continue to remain agile in support of existing U.S. strategy."
He did not provide details on the number of U.S. troops that have been withdrawn or how many remain in the country.
Hifter, the chief of the self-styled Libyan National Army (LNA), ordered his forces on Thursday to seize Tripoli from the rival government of Fayez Serraj.
LNA spokesman Ahmed al-Mismari said Sunday that the offensive targeting Tripoli was going well and that LNA forces were advancing on the city.
"The battle for Tripoli is final and firm in uprooting terrorism," al-Mismari said in a televised press briefing.
LNA jets on Sunday targeted Serraj-aligned forces near Tripoli airport, on the southern outskirts of the city, in support of the ground forces, al-Mismari said.
He added that a counter-attack by the rivals to retake the airport had failed.
The rival sides have both claimed control of Tripoli airport, which has been out of operation since 2014.
Hifter's onslaught on Tripoli has raised global fears of a worsening conflict in Libya, which has been in turmoil since the NATO-backed ouster of its long-time autocrat, Moamer Gaddafi, in 2011.
The warring factions ignored a call by the United Nations to observe a brief humanitarian truce on Sunday on the outskirts of Tripoli in order to evacuate the injured and civilians from the area.
The proposed truce was for two hours, starting from 4 P.M. on the southern edges of Tripoli, the UN Support Mission in Libya said in a tweet.
Civilians trapped in the battle area were urged to remain indoors and to avoid coming near windows for their safety.
"This advice comes after the UN mission failed to convince the two feuding sides of heeding the two-hour truce," Osama Ali, a spokesman for the Tripoli ambulance service, told dpa.
At least 21 people have been killed and 27 others injured since fighting broke out in the area on Thursday, according to a health official in Tripoli.
The dead include two women who were killed after a stray shell hit a house in southern Tripoli, Amin Mohammed, a spokesman for the Tripoli-based Health Ministry, said.
On Saturday, al-Mismari said that 14 pro-Hifter fighters had been killed in the fighting.
The U.S. military said Sunday it was pulling out of Libya as a result of the escalating conflict.
Commander Thomas Waldhauser of the U.S. Africa Command said a contingent of soldiers had been moved out of Libya as a result of the unrest and unpredictable security conditions.
Waldhauser did not clarify how many troops were being removed, nor did he say where they would be relocated.
Libya has at least two competing administrations: one backed by the UN based in Tripoli, and the other in the eastern city of Tobruk, which is allied with Hifter.
Since 2014, Hifter has expanded his forces' foothold in Libya, portraying his campaign as a "war on terrorists."
His opponents accuse him of seeking to establish a military dictatorship and crushing dissent in the country.