Explosions and anti-aircraft fire could be heard in parts of the Libyan capital Tripoli late Saturday, witnesses said.
A Reuters reporter and other residents said they saw a drone or aircraft opening fire, but no more details were immediately available.
Clashes had broken out earlier in Tripoli's suburbs. The fighting followed the revelation Friday that U.S. President Donald Trump spoke by phone earlier in the week to Khalifa Haftar, the leader of the militant group known as the Libyan National Army, and commended him on what he said was Haftar's "significant role in fighting terrorism and securing Libya's oil resources."
The Trump administration did not say why it waited several days to announce the call.
Haftar's LNA forces refuse to recognize the U.N.-supported Tripoli government. They started a campaign April 3 to seize control of the capital. The United Nations has been calling for a cease-fire.
The World Health Organization says more than 200 people have been killed and more than 1,000 wounded since the violence erupted.
Geographically, the LNA has its power in the eastern part of Libya and the Tripoli government controls the west.
The violence deepens the chaos that has gripped the North African country since dictator Moammar Gadhafi was toppled in 2011. The attacks threaten to disrupt oil production, trigger migration across the Mediterranean Sea to Europe, and enable jihadists to exploit the chaos.