Doctors without Borders (MSF) has remarked thousands of refugees, migrants, and asylum seekers arbitrarily held in Libyan detention centers must immediately be released and evacuated to safety out of the country.

MSF, in a report on Friday, urged UN agencies to act during a fragile ceasefire from heavy fighting in Tripoli.

"Several detention centers in Tripoli are on frontlines and thousands of desperate people are still trapped inside," said Ibrahim Younis, MSF's Head of mission for Libya.

Younis indicated that there is a real risk of mass casualties as a result of indiscriminate shelling and artillery fire, saying the supply of food and water has broken down and is now only being provided on an ad-hoc basis.

"Medical care is wholly insufficient as this is mostly provided by international organizations now forced to suspend activities due to the current insecurity." MSF's report says.

It adds that MSF teams could not access refugees and migrants in detention centers since the fighting began on August 26, coming dangerously close to one of the biggest detention centers, holding about 700 people.

"MSF teams were also unable to access another four detention centers where they had been regularly providing health care via mobile clinics." The report reads.

MSF stressed that the resources and mechanisms exist to bring these people to third countries where their claims for asylum or repatriation can be duly processed.

"That's what needs to happen right now, without delay. This is about saving lives." It remarked.

Over 63 people were killed, 12 went missing, 259 injured and about 2000 were displaced in two-week clashes in souther Tripoli districts, according to the Health Ministry and Tripoli Field Hospital.