Hampered by winter weather, frequent aftershocks and the dangers posed by badly damaged buildings, rescuers in Turkey and Syria continue to search for survivors of Monday's earthquake, as the toll passes 5,000 dead.
Turkey has put the latest death toll at 3,419, bringing the confirmed number of dead in the border region between Turkey and Syria to 5,021.
There are fears that that figure will rise, with World Health Organization officials estimating that as many as 20,000 may have died.
A further 20,000 are injured.
Some of the worst devastation occurred near the quake's epicentre between the Turkish cities of Kahramanmaras and Gaziantep,home to two million where entire blocks now lie in ruins under gathering snow.
The Syrian health ministry has reported damage across the provinces of Aleppo, Latakia, Hama and Tartus.
A winter blizzard has covered major roads into the area in ice and snow and officials said three major airports have been rendered inoperable, complicating aid deliveries.
Rapid global mobilisation
Countries around the world have mobilised rapidly to send aid and rescue workers to the affected region.
President Emmanuel Macron said France stood ready to provide emergency aid to Turkey and Syria. "Our thoughts are with the bereaved families," he tweeted.
Israel's Prime Minister Benjamin Netanyahu said he had approved the sending of aid to Syria, whose government does not recognise Israel, after receiving a request through diplomatic channels.
The government will also send humanitarian assistance to Turkey, he said.
A Damascus official has denied that Syria requested help from Israel.
Vast regional impact
Up to 23 million people could be affected by the disaster, the World Health Organization has warned.
"Event overview maps show that potentially 23 million people are exposed, including around five million vulnerable populations," WHO senior emergencies officer Adelheid Marschang told the UN health agency's executive committee.
The impact on infrastructure, particularly health services, will be considerable, particularly in an area already vulnerable after a decade of war, the Islamic State insurgency and a recent cholera epidemic.
