The United States is "deeply concerned" by fighting near Libya's capital Tripoli and is seeking an "immediate halt" to an offensive by the forces of Khalifa Haftar, Secretary of State Mike Pompeo said on Sunday. 

"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," he said in a statement. 

Libya descended into chaos during the 2011 overthrow of Muammar Gaddafi that has seen a bitter rivalry emerge between the Tripoli-based authorities and Haftar's supporters in the east of the country. 

Fighting raged south of Tripoli on Sunday, three days after Haftar launched the offensive to seize the capital, now controlled by a UN-backed unity government and an array of militias. 

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Timeline of Libyan conflicts (2011-present)

But Pompeo stressed that there is "no military solution to the Libya conflict," and urged all parties to "urgently de-escalate the situation." 

"This unilateral military campaign against Tripoli is endangering civilians and undermining prospects for a better future for all Libyans," he said. 

"The United States continues to press Libyan leaders, together with our international partners, to return to political negotiations mediated by UN Special Representative of the Secretary-General Ghassan Salame," he added. "A political solution is the only way to unify the country and provide a plan for security, stability, and prosperity for all Libyans."

The United Nations aims to stage a conference in the southwestern town of Ghadames April 14-16 to weigh elections as a way out of the country's prolonged factional anarchy, which has seen Islamist militants establish a toehold in some areas.

The UN special envoy to Libya, Ghassan Salame, said he was striving to prevent the new crisis from getting out of control. "We have worked for one year for this national conference, we won't give up this political work quickly," he said.

Haftar, 75, who casts himself as a foe of Islamist extremism, was quoted by Al-Arabiya TV as telling Guterres his offensive would continue until terrorism was defeated.

(Cover: Spokesperson of Libya's Government of National Accord Colonel Mohamed Ghnouno holds a press conference in Tripoli, Libya, April 07, 2019. /VCG Photo )