At least nine people were killed overnight Thursday-Friday in heavy clashes between militias in the Libyan capital Tripoli, emergency services said.
Updating an earlier toll, emergency services told Al-Ahrar television a child was among the nine dead and that 25 other people -- including civilians -- were wounded, several of them seriously.
Tensions have been rising for months as two prime ministers vie for power in the North African country, raising fears of renewed conflict two years after a landmark truce ended a ruinous attempt by eastern military chief Khalifa Haftar to seize Tripoli by force.
The latest fighting started with a gunbattle late Thursday in Ain Zara, a densely populated neighbourhood of eastern Tripoli, between the Al-Radaa force and the Tripoli Revolutionaries Brigade, media reports said.
It later spread into other areas, trapping 60 students in university dormitories until they were rescued, Osama Ali of the ambulance service told Al-Ahrar, a news channel.
Hundreds of women attending wedding ceremonies in the Fornaj district were also trapped.
"We spent the night in the basement. Our children were terrified," one resident, Mokhtar al-Mahmoudi, told AFP.
Both groups involved in the fighting are nominally loyal to Abdulhamid Dbeibah's Government of National Accord, appointed last year as part of a United Nations-backed peace process to end more than a decade of violence in oil-rich Libya.
Dbeibah has refused to cede power to Fathi Bashagha, named in February as prime minister by a parliament based in Libya's east after he made a pact with Haftar.
In mid-May Bashagha tried to take up office in the capital but sparked clashes between armed groups supporting him and those backing Dbeibah.
In early July he told AFP that he still intended to enter Tripoli "in the coming days".
Clashes on June 10, involving different militias than this time, left one person dead, a security source said.
But the latest fighting was the first in months to cause civilian casualties in the capital.
Images posted on social media showed dozens of vehicles abandoned, their doors open in the middle of the road, by drivers fleeing the violence.
The unrest forced flights by Libyan Airlines and another carrier, Alamia, to be diverted from Tripoli's Mitiga airport to Misrata, around 200 kilometres (125 miles) east of the capital.
Libya has been gripped by insecurity since a NATO-backed uprising in 2011 toppled and killed dictator Moamer Kadhafi, leaving a power vacuum armed groups have been wrangling for years to fill.