The World Health Organization says 264 people have been killed and 1,266 wounded in three weeks of fighting by rival governments for control of Libya.
The U.N.'s health agency said large numbers of civilians are seeking shelter from the fighting in medical clinics. But it says its immediate concern is for the thousands of people trapped inside government-run detention centers close to the fighting.
Along with a call for an immediate cease-fire, U.N. humanitarian officials say they urgently need more than $10 million to keep helping beleaguered civilians in Libya.
The officials say they have received just 6% of pledges so far.
Meantime, Egyptian President Abdel-Fattah el-Sissi held an emergency meeting of three other African Union members Tuesday to talk about the crisis in Libya.
El-Sissi told diplomats from the Democratic Republic of Congo, Rwanda and South Africa that the international community must "assume its responsibility" and bring the warring parties in Libya back to the peace table.
"The Libyan people have been subject to an abuse of their resources over the past years. Unprecedented chaos caused by militias and terrorist organizations, human trafficking and smuggling due to political disputes between various factions supported by foreign powers. Now the time has come to end this," he said.
Forces loyal to General Khalifa Haftar and his rival government in the east have launched a military offensive against Tripoli and the internationally recognized administration of Prime Minister Fayez al-Sarraj.
The fighting has been primarily centered in the suburbs south of the capital.
Libya has been in chaos since longtime dictator Moammar Gadhafi was toppled and killed in 2011.
Numerous armed factions and militias have been jockeying for power and control of Libya's oil wealth.
The U.N. fears the fighting will not only create a new refugee crisis in North Africa, but that terrorist groups such as Islamic State will take advantage of the crisis to dig in deeper inside Libya.
