(AFP) - At least 150 people were killed when freak floods hit eastern Libya, officials said Monday, after storm Daniel swept the Mediterranean, lashing Turkey, Bulgaria and Greece.

Images filmed by residents of the Libyan disaster area showed massive mudslides, collapsed buildings and entire neighbourhoods submerged under muddy water.

Speaking on Libyan network Almasar, Oussama Hamad, prime minister of the east-based government, reported "more than 2,000 dead and thousands missing" in the city of Derna alone, but no medical sources or emergency services have confirmed such figures.

While media outlets in eastern Libya have largely picked up on Hamad's remarks, separate tolls reported from various areas add up to far lower figures.

Mohamed Massoud, a spokesman for Hamad's Benghazi-based administration, said earlier that "at least 150 people were killed as a result of flooding and torrential rains left by storm Daniel in Derna, Jabal al-Akhdar region and the suburbs of Al-Marj".

"This is besides the massive material damage that struck public and private properties," he told AFP.

Hundreds of residents were still believed to be trapped in difficult-to-reach areas as rescuers, backed by the army, were trying to come to their aid.

East Libyan authorities had "lost contact with nine soldiers during rescue operations", Massoud said.

He said Hamad and the head of a rescue committee as well as other ministers had travelled to Derna to evaluate the extent of the damage.

Experts have described storm Daniel -- which killed at least 27 people when it struck parts of Greece, Turkey and Bulgaria in recent days -- as "extreme in terms of the amount of water falling in a space of 24 hours".

- 'Catastrophic' -

Hamad's government -- which in war-battered Libya rivals a UN-brokered, internationally recognised transitional administration in Tripoli -- on Monday declared Derna a "disaster area".

Libya's western government under Abdelhamid Dbeibah, during an extraordinary ministerial meeting broadcast live on television, announced three days of national mourning and emphasised "the unity of all Libyans" in the face of the disaster.

The National Petroleum Company, which has its main oilfields and terminals in eastern Libya, declared "a state of maximum alert" and suspended flights between production sites where activity was drastically reduced.

A Derna city council official described the situation in the city as "catastrophic" and in need of "national and international intervention", speaking to the local TV channel Libya al-Ahrar.

He reported the collapse of four main bridges, two buildings and two dams in Derna, a city of 100,000 people that lies in a river wadi 900 kilometres (560 miles) east of the capital Tripoli.

Footage broadcast by media outlets showed a massive flood washing through the city, damaging buildings in its path.

In a statement on Facebook, Presidential Council chief Mohamed al-Manfi called for "help from brotherly and friendly countries and international organisations".

Manfi officially declared Derna, Shahat and Al-Bayda a "disaster zone".

The storm struck eastern Libya on Sunday afternoon, hitting the coastal town of Jabal al-Akhdar especially hard, as well as Benghazi, where a curfew was declared and schools closed for several days.

The United Nations mission in Libya on Monday said on X, formerly Twitter, that it was "closely following the emergency caused by severe weather conditions in the eastern region of the country".

It expressed its condolences over the deaths and said it was "ready to support efforts by local authorities and municipalities to respond to this emergency and provide urgent humanitarian assistance".

- More rain expected -

Libya, sitting on Africa's largest-known oil reserves, was plunged into chaos following the 2011 NATO-backed uprising that toppled and killed former dictator Moamer Kadhafi.

Two rival governments based in the west and east have been vying for power, with deadly conflict occasionally erupting.

French President Emmanuel Macron expressed "solidarity with the Libyan people" and said the country was mobilising resources to provide emergency aid.

US State Department Spokesperson Matthew Miller offered "sympathies and condolences" to those affected by the floods, and said Washington was working with the UN and Libyan authorities to help relief efforts.

In Egypt, authorities called for caution on the northern coast, which borders eastern Libya, and announced they were beginning preparations to minimise the impact of storm Daniel.

Weather forecasters predicted more heavy rain there in the coming days.

As the world warms, the atmosphere contains more water vapour, which increases the risk of heavy precipitation in some parts of the world.

Combined with other factors such as urbanisation and land-use planning, these more intense rainfall events contribute to flooding.

© Agence France-Presse