Rescue workers in eastern Turkey pulled a handful of survivors Monday from the rubble of Sunday's powerful 7.2-magnitude earthquake, which killed at least 270 people and injured hundreds more.
As aftershocks continued to rock the area, four people in worst-hit Ercis were extracted from the mounds of debris left by Sunday's quake. Dozens more were thought trapped but still alive.
Rescuers in Ercis, a city of 75,000 located near the Iranian border and about 30 miles north of the quake's epicenter, painstakingly lifted pancaked slaps of concrete and twisted rebar from the piles of rubble in hopes of reaching survivors.
Some 80 multistory buildings collapsed in Ercis.
Yalcin Akay, who was pulled out of what remained of a six-story building with a leg injury, used his cell phone to call police and describe his location, according to state-run Anatolia news agency. Three others, including two children, also were rescued from the same building 20 hours after the quake struck, officials said.
Turkey, a country with a long history of devastating earthquakes, has mobilized a large rescue operation, with government and private aid groups setting up field hospitals, food centers and tents for those left homeless by the disaster.
Turkish Prime Minister Recep Tayyip Erdogan flew to inspect the damage in Ercis. He said "close to all" mud-brick homes in surrounding villages had collapsed in the quake.
Erdogan said Turkey was able to cope for the time being, but Azerbaijan, Iran and Bulgaria sent aid anyway, he said. Israel's defense ministry said Ankara had declined its offer of help.
President Obama said in a statement that the U.S. stands ready to assist if necessary.
"We stand shoulder to shoulder with our Turkish ally in this difficult time, and are ready to assist," Obama said.
Aid groups scrambled to set up tents, field hospitals and kitchens to help the thousands left homeless or those too afraid to re-enter their homes amid more than 100 aftershocks, three of them reaching 4.7 magnitude.
"We stayed outdoors all night. I could not sleep at all. My children, especially the little one, (were) terrified," said Serpil Bilici. She said of her 6-year-old daughter, Rabia: "I grabbed her and rushed out when the quake hit. We were all screaming."
Authorities advised people to stay away from damaged homes, warning they could collapse in the aftershocks. Exhausted residents began sheltering in tents, some set up inside a sports stadium, after many spent the night outdoors lighting fires to keep warm. Others sought shelter with relatives in nearby villages.
The bustling, larger city of Van, about 55 miles south of Ercis, also sustained substantial damage, but Interior Minister Idris Naim Sahin said search efforts there were winding down.
Sahin expected the death toll in Ercis to rise, but not as much as initially feared. He told reporters rescue teams were searching for survivors in the ruins of 47 buildings, including a cafe where dozens could be trapped.
In Ercis, a team specializing in mine disaster rescue combed through the rubble of a student dormitory.
The terrifying moments of the powerful temblor still haunted many.
"I was in the street and saw the buildings sway," Hasan Ceylan, 48, surveying the wreckage of his three businesses, including a grocery store and a veterinary clinic.
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.
The Associated Press and NPR's Peter Kenyon in Istanbul contributed to this report.