A 7.2-magnitude earthquake struck eastern Turkey Sunday, killing at least 138 people as buildings crumpled into rubble. The death toll was expected to rise as rescuers sifted through the rubble and reached outlying villages.

The bustling city of Van sustained substantial damage. About 55 miles (90 kilometers) to the north, Ercis, a city of 75,000 close to the Iranian border and in one of Turkey's most earthquake-prone zones, was also badly hit.

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 the rubble, he said, without citing any estimates.

Residents in Van and Ercis lit campfires, preparing to spend the night outdoors. Rescue efforts went deep into the night under generator-powered floodlights.

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

Check out some photos of the scene.

People sit on a pile of debris after an earthquake in Ercis, near the eastern Turkish city of Van early October 24, 2011
People sit on a pile of debris after an earthquake in Ercis, near the eastern Turkish city of Van early October 24, 2011 Reuters
Yunus, a 13-year-old earthquake survivor, waits to be rescued from under a collapsed building by rescue workers in Ercis, near the eastern Turkish city of Van, early October 24, 2011.
Yunus, a 13-year-old earthquake survivor, waits to be rescued from under a collapsed building by rescue workers in Ercis, near the eastern Turkish city of Van, early October 24, 2011. Reuters
A man receives serum as he waits to be rescued under a collapsed building in Ercis, near the eastern Turkish city of Van, late October 23
A man receives serum as he waits to be rescued under a collapsed building in Ercis, near the eastern Turkish city of Van, late October 23 Reuters
A man reacts as rescue workers try to save his son trapped under debris after an earthquake in Ercis, near the eastern Turkish city of Van, late October 23, 2011.
A man reacts as rescue workers try to save his son trapped under debris after an earthquake in Ercis, near the eastern Turkish city of Van, late October 23, 2011. Reuters
Barack obama Earthquake Barack obama Earthquake