Rescue workers in Turkey are scrambling to dig people out of the rubble after a 7.2 magnitude earthquake struck the eastern Van province.
Prime Minister Tayyip Erdogan said 138 people were killed in Sunday's quake but the number still buried beneath the rubble is unknown.
Ninety-three people died in Van city alone and 45 in the Ercis, Erdogan told reporters, after visiting the devastation wrought by the strong quake.
The death toll will rise further when information from other towns and remote villages comes in, an official at the provincial crisis centre in the city of Van told Reuters news agency.
|Turkish officials estimate that up to 1,000 lives could have been lost in the 7.2 magnitude quake [Reuters]
Up to 600 people are known to have been injured and between 300 and 400 are missing, believed to be buried beneath the rubble of collapsed buildings, the official said.
Earlier, state-run TRT television said at least 85 people were reported killed and the country's seismology institute said up to 1,000 people could be trapped under collapsed buildings.
"We estimate around 1,000 buildings are damaged and our estimate is for hundreds of lives lost. It could be 500 or
1,000," Kandilli Observatory general manager Mustafa Erdik told a news conference.
TRT said 59 people had been killed and 150 others injured in Ercis, while 25 others died in the provincial city of Van. Another person died in the nearby province of Bitlis.
Civilians joined in the desperate search, using their bare hands and working under generator-powered floodlights.
Al Jazeera's Anita McNaught, reporting from Van, said rescuers lacked proper tools to search for survivors and were using equipments from nearby roadworks.
"Everyone here is desperate to help but no one has the right tools and the expertise," she said.
"We're not seeing what we know exists in Turkey, professionally trained earthquake disaster relief teams.
"They are saying they can hear voices, but there are so many other noises here, so it's impossible to pick up anything with any certainty."
The centre of the city was pitch black due to power outages.
Hospital staff in Ercis treated injured people in gardens as the buildings were badly damaged, and the dead were left outside, one nurse said.
"The hospital has been badly damaged, so we can't operate inside," nurse Eda Ekizoglu told CNN Turk.
Hundreds feared killed after Turkey earthquake
"We're giving care in the hospital garden and at a nearby building with a generator," she said.
Authorities had no immediate information about the situation in remote villages.Telecommunication services were down in many areas, making it difficult to assess damage.
"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."
The Turkish Red Crescent said its rescuers pulled several injured people out of the collapsed dormitory in Ercis, which sits on a geological fault line.
It said it was sending tents, blankets and food to the region.
Serious damage and casualties were also reported in the district of Celebibag, near Ercis.
"There are many people under the rubble," Veysel Keser, mayor of Celebibag, told NTV. "Many buildings have collapsed, student dormitories, hotels and gas stations have collapsed."
Six helicopters as well as military cargo planes were sent to the area carrying tents, food and medicine.
China, Japan, the United States, Azerbaijan, several European countries and NATO offered assistance.
Israel also offered "any aid" Turkey might need, despite tensions between the formerly close allies. Ehud Barak, the defence minister, later said Turkey had declined Israeli aid.
A Turkish official told Reuters that Turkey gave Israel the same answer as a dozen other countries which had offered help.
In Yerevan, the capital of neighbouring Armenia, people rushed into the streets fearing buildings would collapse but no damage or injuries were immediately reported.
The earthquake was also felt over the border in northwest Iran, causing some panic in major cities, Iranian media reported.
Major geological faultlines cross Turkey and small earthquakes are a near daily occurrence. Two large quakes in 1999 killed more than 20,000 people in northwest Turkey.
Two people were killed and 79 injured in May when an earthquake shook Simav in northwest Turkey.
Source: Al Jazeera and agencies