As many as 1,000 people were feared killed on Sunday when a powerful earthquake hit southeast Turkey, destroying dozens of buildings and trapping some victims alive under rubble.
As night fell, survivors and emergency workers battled to pull people out of the debris in the city of Van and town of Ercis, where a student dormitory collapsed.
Residents in Van joined in a frantic search, using hands and shovels and working under floodlights and flashlights, hearing voices of survivors crying for help under mounds of shattered concrete in pitch darkness and bitter cold.
"We heard cries and groaning from underneath the debris, we are waiting for the rescue teams to arrive," Halil Celik told Reuters as he stood beside the ruins of building that had collapsed before his eyes.
"All of a sudden, a quake tore down the building in front of me. All the bystanders, we all ran to the building and rescued two injured people from the ruins."
At another site, three teenagers were believed trapped under a collapsed building. People clambered over the masonry, shouting: "Is there anyone there?"
An elderly rescue worker sat sobbing, his exhausted face covered in dust. Police tried to keep onlookers back. Ambulance crews sat waiting to help anyone dragged out of the debris.
Turkey's Kandilli Observatory and Earthquake Research Institute said the magnitude 7.2 earthquake struck at 1041 GMT and was five km (three miles) deep. It was among the strongest in Turkish history, and the worst since 1999.
Deputy Prime Minister Besir Atalay said a dozen buildings collapsed in Van, an ancient city with a population of 1 million. Turkish media said 80 buildings, including a student dormitory, came down in Ercis, a city of 100,000 people near the Iranian border.
"Ambulances, soldiers, emergency teams are everywhere now, working on getting people out of collapsed buildings. I have seen many dead bodies being taken out, the teams are trying to find people alive," said a Reuters photographer in Ercis, some 100 km (60 miles) north of Van.
Kandilli Observatory general manager Mustafa Erdik told a news conference he estimated hundreds of lives had been lost. "It could be 500 or 1,000," he added. He said he based his estimate on the magnitude of the earthquake and quality of construction.
A nurse at a public hospital in Ercis said hospital workers were attending the wounded in the hospital garden because the building was badly damaged.
"We can't count dead or injured because we're not inside the hospital. There should be more than 100 dead bodies left next to the hospital. We left them there because it's dark and we didnt want to step on bodies," Eda Ekizoglu told CNN Turk television.
Prime Minister Tayyip Erdogan was travelling to Van and the cabinet was expected to discuss the quake on Monday morning.
"A lot of buildings collapsed, many people were killed, but we don't know the number. We are waiting for emergency help, it's very urgent," Zulfukar Arapoglu, the mayor of Ercis, told news broadcaster NTV.
"We need tents urgently and rescue teams. We don't have any ambulances, and we only have one hospital. We have many killed and injured," Arapoglu said.
Turkey's Red Crescent said one of its local teams was helping to rescue people from a student residence in Ercis. It sent had sent 1,200 tents, more than 4,000 blankets, stoves and food supplies, along with two mobile bakeries.
More than 70 aftershocks shook the area, further unsettling residents who ran into the streets when the initial quake struck. Television pictures showed rooms shaking and furniture toppling as people ran from one building.
Dozens of emergency workers and residents scrambled over a multi-storey building in Van as they searched for anyone trapped inside. Elsewhere, dazed survivors wandered past vehicles crushed by falling masonry.
Some 50 injured people were taken to hospital in Van, state-run Anatolian news agency reported.
Turkish media said phone lines and electricity had been cut off. The quake's epicentre was at the village of Tabanli, 20 km north of Van city, Kandilli said.
International offers of aid poured in from NATO, China, Japan, the United States, Azerbaijan, European countries and Israel, whose ties with Ankara have soured since Israeli commandoes killed nine Turks during a raid on an aid flotilla bound for the Israeli-blockaded Gaza Strip in 2010.
Serzh Sarksyan, the president of Turkey's longtime regional rival Armenia, phoned Turkey's President Abdullah Gul to offer his condolences. Major geological fault lines cross Turkey and there are small earthquakes almost daily. Two large quakes in 1999 killed more than 20,000 people in northwest Turkey.
An earthquake struck Van province in November 1976, with 5,291 confirmed dead. Two people were killed and 79 injured in May when an earthquake shook Simav in northwest Turkey.