Rescue teams are still searching for victims in collapsed buildings after two strong earthquakes hit northwestern Iran, killing at least 250 people and injuring 2,600 others.

The 6.4 and 6.3 magnitude quakes struck minutes apart late Saturday afternoon, leveling several villages near the city of Tabriz and seriously damaging several others.

The United States on Sunday offered help and condolences to the people of Iran. The White House statement was addressed to the “Iranian people” and said the U.S. stands ready “to offer assistance in this difficult time,” but made no mention of the Iranian government.

Dozens of aftershocks have rumbled through the area, prompting thousands of people to spend the night outdoors.

The Red Crescent aid society says it has given emergency shelter to thousands of people so far and is sending in more supplies.

Earthquakes are common in Iran, but few are significant enough to be noticed. The last major earthquake in Iran was a magnitude 6.6 quake in 2003 in the southeastern city of Bam, where 30,000 people died.