Rice was due to leave for London, where she was scheduled to attend a meeting of six major powers on whether to urge the United Nations to slap sanctions on Iran over its suspect nuclear programme.

The source said Rice's airplane had been damaged by a "piece of plastic," and the security officials did not want to risk using the aircraft. As a result, the entourage was awaiting the arrival in Arbil of a substitute airplane.

There was no indication of how long the delay would last.