A state of emergency in Libya has put lives in “grave danger,” Doctors Without Borders said as the international NGO added that it was “highly concerned” for the Libyan residents, refugees and migrants in a country that was not safe.

On Sunday, conflict erupted between rival armed groups in Tripoli and heavy shelling in residential areas has led to an unspecified number of casualties, MSF said in a statement.

The fighting further jeopardised the lives of an estimated 8,000 refugees, asylum seekers and migrants who have been trapped and arbitrarily held in closed detention centres throughout the city, it pointed out.

“Many have fled from war-torn countries or have spent months in horrible conditions, while being held by human traffickers before they were put in these closed detention centres. These people are already extremely vulnerable, and now they find themselves trapped in yet another conflict without the ability to escape,” said Ibrahim Younis, MSF’s head of mission in Libya.

They should not be held captive but immediately released and evacuated to a safe country, the internationa NGO said.

The fighting erupted between armed groups from Tripoli against others from a town to the south. The Libyan government issued a statement on Sunday urging rival militias to stop and obey a UN brokered ceasefire.

MSF said that the humanitarian needs in and outside detention centres “have grown from already alarming levels” and, together with other NGOs have limited access to people in need of assistance.

It called on European governments to acknowledge that Libya “is not a place of safety”.

UN Secretary General Antonio Guterres  said the “indiscriminate use of force is a violation of international humanitarian and human rights law” and urged “all parties to grant humanitarian relief for those in need”.

On Saturday, the US, UK, France and Italy called for an immediate end to deadly violence in Libya’s capital.