Libya’s devastated eastern city of Derna is counting its dead as rescuers continue to pull out more bodies from the rubble of the city battered by flash floods that have killed thousands and the Red Cross warning that 10,000 are missing.

According to international media reports, an official of the Tripoli-based national unity government said on Wednesday that the death toll had crossed 6,000 and thousands are still missing since the floods unleashed by Storm Daniel.

A Libyan minister also sought urgent international help, saying the country did not have the expertise and experience to deal with a calamity of such proportions.

Tamer Ramadan of the International Federation of Red Cross and Red Crescent Societies said on Tuesday that “the death toll is huge and might reach thousands”.

“We don’t have a definite number right now,” he said, quoting the organisation’s independent sources as saying “the number of missing people is hitting 10,000 persons so far”.

The city of Derna, a 300-kilometre drive east of Benghazi, is ringed by hills and bisected by what is normally a dry riverbed in summer, but which became a raging torrent of mud-brown water that also swept away several major bridges.

Derna was home to about 100,000 people, and many of its multi-storey buildings on the banks of the riverbed collapsed, with people, their homes and cars vanishing in the raging waters.

With global concern about the disaster spreading, several nations offered urgent aid and rescue teams to help the war-scarred country that has been overwhelmed by what one UN official called “a calamity of epic proportions”.

Elsewhere in eastern Libya, aid group the Norwegian Refugee Council said on Tuesday that “entire villages have been overwhelmed by the floods and the death toll continues to rise”.