At least 10,000 people were feared missing in Libya on Tuesday in floods caused by a huge storm, which burst dams, swept away buildings and wiped out as much as a quarter of the eastern city of Derna.

More than 1,000 bodies had already been recovered in Derna alone, and officials expected the death toll would be much higher, after Storm Daniel barrelled across the Mediterranean into a country crumbling from more than a decade of conflict.

A Reuters journalist on the way to Derna, a coastal city of around 125,000 inhabitants, saw vehicles overturned on the edges of roads, trees knocked down, and abandoned, flooded houses.

"I returned from Derna. It is very disastrous. Bodies are lying everywhere - in the sea, in the valleys, under the buildings," Hichem Abu Chkiouat, minister of civil aviation and member of the emergency committee in the administration that controls the east, told Reuters by phone.

"The number of bodies recovered in Derna is more 1,000," he said. "I am not exaggerating when I say that 25% of the city has disappeared. Many, many buildings have collapsed."

Abu Chkiouat later told Al Jazeera that he expected the total number of dead across the country to reach more than 2,500, as the number of missing people was rising.

Tamer Ramadan, head of a delegation of the International Federation of the Red Cross and Red Crescent Societies (IFRC), told reporters in Geneva via video link from Tunisia: "We can confirm from our independent sources of information that the number of missing people is hitting 10,000 so far."

Videos showed a wide torrent running through Derna's city centre after dams burst. Ruined buildings stood on either side.

Another video shared on Facebook, which Reuters could not independently verify, appeared to show dozens of bodies covered in blankets on the pavements.

Footage broadcast by Libyan TV station al-Masar showed people searching for bodies and men in a rubber boat retrieving one from the sea.

"We have nothing to save people ... no machines...we are asking for urgent help," Khalifah Touil, an ambulance worker, said in an al-Masar report.

Derna is bisected by a seasonal river that flows from highlands to the south, and normally protected from flooding by dams. A video posted on social media the remants of a collapsed dam 11.5 km (7 miles) upstream of the city where two river valleys converged, now surrounded by huge pools of mud-coloured water.

"There used to be a dam," a voice can be heard saying in the video. Reuters confirmed the location based on the images.

Convoys of aid and assistance were heading towards the city.

Libya is politically divided between east and west and public services have crumbled since a 2011 NATO-backed uprising that prompted years of conflict.

The internationally recognised government in Tripoli does not control eastern areas but has dispatched aid to Derna, with at least one relief flight leaving from the western city of Misrata on Tuesday, a Reuters journalist on the plane said.

Other countries, including the United States, also said they would help.