WASHINGTON — The United States will offer humanitarian aid to Iran after an earthquake in the southern part of the country killed thousands, the White House said Friday.

"I extend my condolences to all those touched by this tragedy," President Bush said in a statement Friday. "The thoughts of all Americans are with the victims and their families at this time, and we stand ready to help the people of Iran."

A senior administration official said it was too early to say what form the aid might take. The Red Cross, the Iranian Red Crescent Society and the United Nations are assessing damage, and the U.S. assistance will reflect what those organizations and what Tehran says Iran needs, the official said.

The 6.5-magnitude earthquake struck about 5:30 a.m., local time, collapsing buildings in the city of Bam in southeastern Iran, severing power lines and shutting down water service.

Bush said: "We are greatly saddened by the loss of life, injuries, and widespread damage to this ancient city."

Bush had not spoken to any Iranian leaders, said his spokesman, Scott McClellan, who was flying with the president to Texas for a weeklong holiday break at his ranch in Crawford.

McClellan said he did not know whether any aid discussions would be carried out through an intermediary organization or a third country.

The United States does not have formal diplomatic relations with Iran, which Bush described, along with Iraq and North Korea, as part of the "axis of evil" in his 2002 State of the Union speech. The United States says Iran sponsors terrorism, is trying to acquire nuclear weapons and has a poor human rights record.

U.S. sanctions prohibit most trade with Iran and most dealings between the countries are conducted through the auspices of Switzerland, Pakistan or international organizations.

Last year, United States used the United Nations to channel $300,000 in humanitarian aid to Iran after a magnitude 6.1 million quake killed 245 people in the northwestern part of the country.