Rescuers scrambled through the rubble in a desperate search on Monday for survivors of an earthquake that killed at least 264 people in Turkey as residents fled the scenes of carnage.

People living in eastern Van province issued cries for help on Twitter, giving out the addresses of collapsed buildings and the number of people trapped under the debris, as hundreds of rescuers worked round the clock.

Two children were plucked alive from the wreckage of a collapsed building in the town of Ercis but it was a rare slice of good news in an otherwise grim task for the rescue teams.

Many students were believed to be buried in Ercis, the town which felt the full brunt of the quake, after a dormitory collapsed and several student houses crumbled.

A total of 264 people were confirmed to have been killed by the 7.2 magnitude earthquake which struck around lunchtime on Sunday, according to Idris Naim Sener, the country's interior minister.

The government said that a total of 970 buildings had collapsed as a result of the quake and aftershocks.

One resident of Ercis recounted the moment when disaster struck and how many had been forced to sleep outside overnight in freezing temperatures.

"We couldn't understand what was going on -- all of a sudden there was dust everywhere, our eyes were full of dust, and we were thrown against the walls and furniture. It lasted 20 seconds," said 23-year-old Yunus Ozmen.

"We spent the night outside in the street and made a fire to keep warm."

His neighbour Abdul Hadi Isik said that his aunt and her children were buried under the rubble.

"There is no hope left," he added.

AFP journalists in Ercis reported that the rescue effort was being hampered by a lack of electricity and water.

Many of the town's residents were fleeing the town while police and soldiers kept watching around crumbled buildings to prevent looting.

While scores of multi-storey buildings had collapsed, most single-storey houses remained intact.

"As the number of storeys increase, the performance of buildings decrease, combined with lack of quality in materials and construction skills," Professor Ahmet Yakut told NTV.

In the province's main city of Van, authorities shut down Yuzunci Yil University and sent more than 4,000 students back to their home towns, the Anatolia news agency said.

Some 200 inmates fled the province's main prison when the building was damaged in the quake, media reports said, adding that 50 of them returned to prison later after seeing their families.

Prime Minister Recep Tayyip Erdogan rushed on Sunday to Van, a mainly Kurdish-populated region.

Turkey mobilised some 2,400 search and rescue teams from 45 cities as well as 108 ambulances, including sefven air ambulances to speed to the aid of the victims, the emergency unit of the prime ministry said.

A search and rescue team of around 650 people was working in Ercis, while another 300 people were in Van city center, Anatolia said.

The military said six battalions were also involved in search and rescue efforts.

Six helicopters, including four helicopter ambulances, as well as C-130 military cargo planes were dispatched to the area carrying tents, food and medicine.

Officials distributed water, biscuits and milk to Ercis survivors, who spent the night outside collapsed houses where many of their relatives remained trapped.

The Turkish Red Crescent sent some 7,500 tents, more than 22,000 blankets, almost 4,000 heaters and 1,000 body bags to the region, Anatolia said.

A mobile bakery and 21 mobile kitchens were also sent to Van, it added. Officials started to erect a tent city in Ercis stadium, the organisation said on its website.

US President Barack Obama said he had been following reports of the disaster "with great concern" and offered his condolences and help to the victims.

The quake was also felt across the border in northwestern Iran, causing some panic in major cities, Iranian media reported. They did not report any deaths or serious damage.

Iran has sent 20 rescuers, 20 ambulances, a field hospital, food supplies and 50 tents for emergency shelter to Van, which lies just over the border with Iran,

In 1999, two strong quakes in northwest Turkey's heavily populated and industrialised regions left some 20,000 dead. A powerful earthquake in the town of Caldiran in Van province killed 3,840 people in 1976.