DERNA, Libya/Geneva, Sept. 15 (Reuters) Residents and rescue workers in the devastated Libyan city of Derna are struggling to cope with the thousands of corpses washing up or decaying under rubble after a flood that smashed down buildings and swept people to sea.

The World Health Organisation and other aid groups urged authorities in Libya to stop burying flood victims in mass graves, saying these could bring long-term mental distress to families or cause health risks if located near water.

A U.N. report said more than 1,000 people had so far been buried in that manner since Libya, a nation divided by a decade of conflict and political chaos, was hit on Sunday by torrential rain that caused two dams to burst.

Thousands were killed, and thousands more are missing.

“Bodies are littering the streets, washing back on shore, and are buried under collapsed buildings and debris. In just two hours, one of my colleagues counted over 200 bodies on the beach near Derna,” Bilal Sablouh, International Committee of the Red Cross (ICRC) forensics manager for Africa, told a briefing in Geneva.