Over 100 refugees died in a shipwreck off the Libyan coast on September 1, and the survivors have been held in arbitrary detention in the country, international humanitarian non-governmental organisation Doctors Without Borders said on Monday. The survivors include people with severe burns, pregnant women and children, the NGO said.

The disaster took place after two rubber boats carrying hundreds of people from different countries left the Libyan coast early on September 1. One of the boats deflated and sank, leading to many deaths, Doctors Without Borders said.

The Libyan Coast Guard rescued 276 people from the two boats, though only two bodies were found. Doctors Without Borders said it provided urgent medical assistance to the wounded. A team also treated survivors for chemical burns, which were caused when the boat’s fuel leaked.

“We managed to treat 18 urgent cases – among them were nine people suffering from extensive chemical burns,” Jai Defranciscis, a nurse working for the NGO in Misrata, northwestern Libya said. “We organized a referral to the hospital for a patient in particularly critical condition. Without quick access to specialized intensive care, the person would have died.”

After medical treatment, the survivors were transferred to a detention center under the control of the Libyan authorities. However, Defranciscis expressed worry for the patients. “How can they recover when locked inside cells, in very poor hygiene conditions and sleeping on blankets or mattresses placed on the floor that cause incredible pain for those suffering from severe burns?” Jai Defranciscis asked. “Some of them cannot even sit or walk. We have started to see patients with severe chest infections like pneumonia, caused by being in the water for such a long time.”

The NGO urged the United Nations Human Rights Council and “safe countries” to expedite the evacuation of refugees and asylum seekers from Libya, citing the ongoing war in the country. It also asked European countries and Libyan authorities to stop intercepting people fleeing by sea and returning them to Libya.