An earthquake of 7.3 magnitude hit eastern Turkey on Sunday, leaving dozens of people injured after several buildings collapsed, seismologists and reports said.
Turkey's seismology institute predicts 500 to 1,000 dead in earthquake.
Turkey's Kandilli Observatory estimates that some 500 to 1,000 people were killed in a powerful earthquake in southeast Turkey's Van province on Sunday, broadcaster CNN Turk reported.
Separately, Deputy Prime Minister Besir Atalay told reporters some 10 buildings had collapsed in Van city and around 25-30 buildings collapsed in the nearby district of Ercis.
At least 50 people were taken to hospital in the city of Van, Anatolia news agency said. There were no immediate reports of deaths but officials warned that they were struggling to assess the full extent of the damage.
"Two buildings collapsed," Van Mayor Bekir Kaya told the NTV television in an initial assessment.
"People are panicked. The telecommunication services have collapsed. We cannot reach anybody," he said.
The US Geological Survey measured the quake at 7.3 magnitude and said that an aftershock was of 5.6 magnitude had also been registered. The epicentre of the aftershock, which occurred at 1056 GMT, was located 19km northeast of Van, the institute added.
The epicentre of the quake, which struck around 1041 GMT, was at Tabanli in Van province, said the Kandilli seismological institute in Istanbul.
The Turkish institute said that there two aftershocks which in particular impacted on Ilikaynak and Gedikbulak villages.
The quake was also felt in neighbouring provinces, Turkish media reported.
Prime Minister Recep Tayyip Erdogan has cancelled official programmes and was due to visit the quake region on Sunday, said NTV.
Van, a city of 380,000 inhabitants, is 1,234 km from the capital Ankara.
The city airport received damage from the quake and planes are being directed to the Erzurum province, around 400 km from Van, media reported.
Turkey is earthquake-prone due to being crossed by several fault lines.
In 1999, two strong quakes in the heavily-populated and industrialised regions of northwest Turkey left some 20,000 dead.
An earthquake in Kutahya province in 1970 killed more than 1,000 people. -- AP