No military intervention on the table for Libya: Kerry

"Our tools are diplomacy. We are not looking at other options," Kerry told journalists alongside his Italian counterpart Paolo Gentiloni following a summit in Rome on the future of countries in the Mediterranean region.

"I don't think any country is prepared to engage in military action."

Kerry said that diplomatic efforts had made progress, disagreeing with Gentiloni who said that negotiations "have not yet produced results".

"There has been a significant shift in the last month of efforts diplomatically to bring general (Khalifa) Haftar to the table... and create a series of meetings to try to resolve some differences," said Kerry, referring to the military strongman who has refused to support a UN-backed unity government.

He instead supports a parallel authority, based in eastern Libya near the border with Egypt, that controls much of the country's oil production.

Fighting between rival militias erupted in Tripoli on Thursday and continued on Friday, with shooting heard throughout the day as most residents stayed at home.

The city is controlled by a loose alliance of militias of different political and religious factions, and clashes between them are an almost daily occurrence.

At least eight people were killed on Thursday and Friday, a source at the al-Khadhra hospital in Tripoli said.

Five years after Libya's 2011 revolution that toppled longtime dictator Muammer Gaddafi, the country remains embroiled in violence and political chaos as the militias and two rival governments vie for power.