BEIRUT, JUNE 30 -- Iranian Revolutionary Guards have smuggled two American hostages from Lebanon to Iran, hiding them in coffins part of the way, a Shiite Moslem source said today.

A top U.S. official expressed skepticism about the report and Iran's foreign minister denied it.

The source told The Associated Press the Americans were "probably Terry Anderson and Thomas Sutherland," who were seized separately more than two years ago by Shiite extremists loyal to Iran. The source has been reliable in the past on information regarding foreign hostages.

According to the Shiite source, who spoke on condition of anonymity, transfer of the Americans to Iran led Syria to impose travel restrictions on Revolutionary Guards based in the Bekaa Valley of east Lebanon and on Iranian diplomats.

The source said the two Americans were taken from Lebanon to the Iranian Embassy in Damascus, the Syrian capital, late in May in coffins purported to contain the bodies of "Revolutionary Guard martyrs killed in action against Israel."

The coffins went from the Bekaa Valley to Damascus in a Revolutionary Guard jeep on a military road, the source said, and "an Iranian Embassy car with a diplomatic license plate transported them from Damascus to Iran via Turkey."

Foreign Minister Ali Akbar Velayati, asked in Vienna today about reports that American hostages were taken to Iran, said, "We categorically deny them."

In Washington, national security adviser Frank Carlucci said, "I've seen these reports, and I think there is some reason to question them."