Up to 1,000 people are feared dead in a powerful earthquake in eastern Turkey, according to initial estimates.

Turkey's Kandilli Observatory said the death toll could be between 500 and 1,000. At least 35 buildings are reported to have collapsed.

The earthquake, with a preliminary magnitude of 7.2, struck in the Van province near the Iranian border on Sunday. The epicentre was below the village of Tabanli, near the city of Van.

"The quake was strongly felt in Van and neighbouring towns and caused damage and deaths, based on initial assessments," the Turkish prime minister's office said.

Ten buildings collapsed in Van and 25-30 in neighbouring Ercis, officials said. Several strong aftershocks were reported.

"There are so many dead. Several buildings have collapsed. There is too much destruction," Zulfikar Arapoglu, the mayor of Ercis, told NTV television. "We need urgent aid. We need medics."

Serious damage and casualties were reported in the district of Celebibag. The mayor, Veysel Keser, told NTV: "There are many people under the rubble. People are in agony, we can hear their screams for help. We need urgent help.

"It's a great disaster. Many buildings have collapsed, student dormitories, hotels and gas stations have collapsed."

Some houses collapsed in the province of Bitlis, and in nearby Mus the quake toppled the minarets of two mosques. NTV said Van's airport was damaged and planes were diverted to neighbouring cities.

Rescue workers and residents using their bare hands and shovels struggled to free people believed to be trapped under collapsed buildings, television footage showed.

At least 50 people were treated for injuries in the courtyard of the state hospital in Van, said the state-run Anatolia news agency.

Earthquakes are frequent in Turkey. In 1999, about 18,000 people were killed by two powerful earthquakes that struck north-west Turkey. Authorities blamed shoddy construction for many of the deaths.