Libyan National Army (LNA) members, commanded by Khalifa Haftar, head out of Benghazi to reinforce the troops advancing to Tripoli, in Benghazi, Libya April 7, 2019. REUTERS/Esam Omran Al-Fetori

WASHINGTON (Reuters) - The United States called on Sunday for an immediate halt to military operations in Libya as the Libyan National Army headed by Khalifa Haftar advanced on the capital, Tripoli.

Secretary of State Mike Pompeo said in a statement that Washington was “deeply concerned about fighting near Tripoli” and urged talks to end the fighting.

“We have made clear that we oppose the military offensive by Khalifa Haftar’s forces and urge the immediate halt to these military operations against the Libyan capital,” Pompeo said in urging de-escalation.

Eleven people were killed and 23 wounded in clashes in southern Tripoli, the Health Ministry of the U.N.-backed Libyan government of National Accord said late on Sunday. The ministry gave no details of whether the casualties were civilians or fighters.

Lawless since 2011 when Muammar Gaddafi was toppled by rebels backed by NATO air strikes, Libya has become the transit point for hundreds of thousands of migrants trekking across the Sahara in hopes of crossing the Mediterranean Sea to reach Europe.

Haftar, 75, who casts himself as a foe of Islamist extremism but is viewed by opponents as a new dictator in the mold of Gaddafi, enjoys the backing of Egypt and the United Arab Emirates, which see him as a bulwark against Islamists and have supported him militarily, according to U.N. reports.

Haftar’s forces carried out air strikes on southern Tripoli on Sunday and made progress toward the city center, residents said.

The offensive, which began last week, intensifies a power struggle that has fractured the oil and gas producer.

The fighting has taken the United Nations by surprise and undermined plans to find agreement on a road map for elections to resolve the protracted instability in Libya.