ANKARA, Turkey (AP) _ Cries of panic and horror filled the air as a 7.2-magnitude earthquake struck eastern Turkey, killing at least 138 people as buildings pancaked and crumpled into rubble. The death toll was expected to rise as rescuers sifted through the rubble and reached outlying villages.

Tens of thousands fled into the streets running, screaming or trying to reach relatives on mobile phones as apartment and office buildings cracked or collapsed. As the full extent of the damage became clear, survivors dug in with shovels or even their bare hands, desperately trying to rescue the trapped and the injured.

“There are many people under the rubble,” Veysel Keser, the mayor of the district of Celebibag, told NTV. “People are in agony. We can hear their screams for help.”

Celebibag is near the hardest-hit area: Ercis, an eastern city of 75,000 close to the Iranian border and on one of Turkey's most earthquake-prone zones. The bustling city of Van, about 55 miles (90 kilometers) south of Ecris, also sustained substantial damage. Highways in the area caved in. The temblor struck at 1:41 p.m. (1041 GMT; 6:41 a.m. EDT), the U.S. Geological Survey said.

Prime Minister Recep Tayyip Erdogan said at least 93 people were killed in Van, 45 others died in Ercis, and about 350 were injured. Several people were still trapped under rubble, he said, without citing any estimates.

Erdogan said rescue work would continue through the night.

Up to 80 buildings collapsed in Ercis, including a dormitory, and 10 buildings collapsed in Van, the Turkish Red Crescent said. The sheer number of collapsed buildings gave rise to fears that the death toll could rise substantially.

U.S. scientists recorded over 100 aftershocks in eastern Turkey within 10 hours of the quake, including one with a magnitude of 6.0. Authorities advised people to stay away from damaged homes, warning they could collapse in the aftershocks.

Residents in Van and Ercis lit campfires, preparing to spend the night outdoors while the Red Crescent began setting up tents in a stadium. Others sought shelter with relatives in nearby villages.

Rescue efforts went deep into the night under generator-powered floodlights. Workers tied steel rods around large concrete slabs in Van, then lifted them with heavy machinery.

Residents sobbed outside the ruins of one flattened eight-story building, hoping that missing relatives would be found. Witnesses said eight people were pulled from the rubble, but frequent aftershocks hampered search efforts. By late evening, some joy emerged as a ninth, a teenage girl, was pulled out alive.

Erdogan urged residents to stay away from damaged buildings and promised assistance to all survivors.

“We won't leave anyone to fend for themselves in the cold of winter,” he said.

Around 1,275 rescue teams from 38 provinces were being sent to the region, officials said, and troops were also assisting search-and-rescue efforts.

In Ercis, heavy machinery halted and people were ordered to keep silent as rescuers tried to listen for possible survivors inside a seven-story building housing 28 families, NTV reported.

Some inmates escaped a prison in Van after one of its walls collapsed. TRT television said around 150 inmates had fled, but a prison official said the number was much smaller and many later returned.

Nazmi Gur, a legislator from Van, said his nephew's funeral ceremony was cut short due to the quake and he rushed back to help.

“We managed to rescue a few people but I saw at least five bodies,” Gur told The Associated Press. “It was such a powerful temblor. It lasted for such a long time,”

“But now we have no electricity, there is no heating, everyone is outside in the cold,” he added.

Authorities had no information yet on remote villages but the provincial governor was touring the region by helicopter and the government sent in tents, field kitchens and blankets.

The earthquake also shook buildings in neighboring Armenia and Iran.

In the Armenian capital of Yerevan, 100 miles (160 kilometers) from Ercis, people rushed into the streets in fear but no damage or injuries were reported. Armenia was the site of a devastating earthquake in 1988 that killed 25,000 people.

Sunday's quake caused panic in several Iranian towns close to the Turkish border and caused cracks in buildings in the city of Chaldoran, Iranian state TV reported.

Leaders around the world conveyed their condolences and offered assistance.

“We stand shoulder to shoulder with our Turkish ally in this difficult time, and are ready to assist,” U.S. President Barack Obama said.

Israeli President Shimon Peres telephoned Turkish President Abdullah Gul to offer assistance.

“Israel shares in your sorrow,” Peres said in a statement. “Israel is ready to render any assistance that may be required anywhere in Turkey, at any time.”

The offer came despite a rift in relations following an 2010 Israeli navy raid on a Gaza-bound aid flotilla that left nine Turks dead. Greece, which has a deep dispute with Turkey over the divided island of Cyprus, also offered to send in a special earthquake rescue team.

Turkey lies in one of the world's most active seismic zones and is crossed by numerous fault lines. In 1999, two earthquakes with a magnitude of more than 7 struck northwestern Turkey, killing about 18,000 people.

More recently, a 6.0-magnitude quake in March 2010 killed 51 people in eastern Turkey, while in 2003, a 6.4-magnitude earthquake killed 177 people in the southeastern city of Bingol.

Istanbul, the country's largest city with more than 12 million people, lies in northwestern Turkey near a major fault line. Experts have warned that overcrowding and shoddy construction in Istanbul could kill tens of thousands if a major earthquake struck.