UP TO 20,000 are now feared dead in the devastating flood in Libya, authorities said today.

Derna, the city worst hit by the disaster, has buried thousands of people in mass graves.

The latest estimated death toll came as search teams scoured the ruins left by the floodwaters.

The deluge swept away entire families on Sunday night and exposed vulnerabilities in the oil-rich country, which has been mired in conflict since a 2011 uprising overthrew veteran dictator Colonel Muammar Gadaffi.

Health officials have confirmed 5,100 deaths and say that many thousands of people are still missing.

An unusually strong Mediterranean storm caused deadly flooding in towns across eastern Libya, with Derna taking the brunt when the dams upriver from the city collapsed.

Floodwaters washed down Wadi Derna, a valley that cuts through the city, crashing through buildings and washing people out to sea.

The startling devastation reflected Storm Daniel’s intensity, but also the vulnerability of Libya, which lacks a single central government.

The country is ruled by one regime in the east and a rival one in the west which has led to widespread neglect of infrastructure.

The dams that collapsed outside Derna were built in the 1970s and had not been maintained for years, local media reported.

Derna has begun burying its dead, mostly in mass graves, said eastern Libya’s Health Minister Othman Abduljaleel.

More than 3,000 bodies were buried by today morning, the minister said, while another 2,000 were still being processed. 

He said most of the dead had been buried in mass graves outside Derna, while others were transferred to nearby towns and cities.

Mr Abduljaleel added that rescue teams were still searching wrecked buildings in the city centre, while divers were combing the sea off Derna.

Derna Mayor Abdel-Raham al-Ghaithi predicted that the death toll could climb to about 20,000, given the number of districts that were washed out.

The storm also killed about 170 people in other parts of eastern Libya, including the towns of Bayda, Susa, Um Razaz and Marj, the health minister said.

The floods have left at least 30,000 people displaced in Derna, according to the International Organisation for Migration, and several thousand others were forced to leave their homes in other eastern towns, the United Nations agency said.

The floods damaged or destroyed many roads giving access to Derna, which has severely hampered the arrival of international rescue teams and humanitarian assistance.

To donate to UN refugee agency’s emergency appeal, visit www.unrefugees.org.uk/libyafloods.