LIBYAN authorities blocked civilians from entering the flood-devastated eastern city of Derna on Friday so search teams could look through the mud and wrecked buildings for 10,100 people still missing after the known toll rose to 11,300 dead.

The disaster after two dams collapsed in heavy rains and sent a massive flood gushing into the Mediterranean city early on Monday underscored the storm's intensity but also Libya’s vulnerability. 

The oil-rich state has been in crisis since 2011 when the US administration of Barack Obama launched an attack on Libya which led to the killing of the country’s long time leader Muammar Gadaffi.

Derna was being evacuated and only search-and-rescue teams would be allowed to enter, Salam al-Fergany, director general of the Ambulance and Emergency Service in eastern Libya, announced late Thursday.

The disaster has brought rare unity, as government agencies across Libya’s factional divide rushed to help the affected areas. 

Relief efforts have been slowed by the destruction after several bridges that connect the city were destroyed.

The Libyan Red Crescent said as of Thursday some 11,300 people in Derna had died and another 10,100 were reported missing. 

The devastating Mediterranean Storm Daniel also killed about 170 people elsewhere in the country.

Eastern Libya’s Health Minister, Othman Abduljaleel, has said the burials so far were in mass graves outside Derna and nearby towns and cities.

Mr Abduljaleel said rescue teams were searching wrecked buildings in the city centre and divers were combing the sea off Derna.

Lori Hieber Girardet, the head of the risk knowledge branch of the United Nations office for disaster risk reduction, said years of chaos and conflict meant that Libyan “government institutions are not functioning as they should.”

As a result, she said, “the amount of attention that should be paid to disaster management and to disaster risk management isn’t adequate.”