The United States has sent more than 80 disaster experts to Iran and committed some 70 tons of relief supplies. And the Bush administration is making clear it is prepared to provide additional help if needed, despite the two countries long-standing political differences.

Briefing reporters here, State Department spokesman Adam Ereli said Deputy Secretary of State Richard Armitage telephoned Iran's ambassador to the United Nations, Mohammed Zarif, Saturday, when the magnitude of the disaster was becoming clear, to officially extend an offer of U.S. earthquake aid. "He spoke to him in Tehran. He noted that this was a humanitarian tragedy that transcended political considerations and offered the support of the United States to deal with the tragedy of the earthquake. They spoke for a short period of time, and the Iranian permanent representative called back to accept the offer of assistance," he said.

The United States and Iran have not had diplomatic relations since the Islamic revolution and takeover of the U.S. embassy in Tehran in 1979, but officials of the two governments do occasionally meet on issues of mutual concern, including developments in Iraq and Afghanistan.

A U.S. Air Force C-130 cargo plane carrying nine tons of medicine and food that landed Sunday at the Iranian city of Kerman, northwest of the earthquake site, was the first U.S. flight to Iran since the embassy hostage crisis ended in 1981.

Several other U.S. supply aircraft have since arrived, including a flight that carried 84 American relief and rescue workers. Among them an 11 member urban search and rescue team from Fairfax County, Virginia, near Washington.

A State Department spokesman said Sunday the earthquake cooperation would not alter what he said were grave U.S. concerns about Iranian policies, including what U.S. official say is that country's support for radicals opposed to Middle East peace efforts and its efforts to acquire nuclear weapons.