Lawmaker Joe Lieberman said Sunday on U.S. television that he considered the claims little more than "Iranian bluster."
Earlier Sunday, a senior Iranian commander declared Tehran had reverse-engineered the drone and begun building a copy.
Iranian news agencies quoted General Amir Ali Hajizadeh, chief of the aerospace division of Iran's Revolutionary Guards, as saying experts also are recovering data from the RQ-170 Sentinel drone captured in December in eastern Iran.
U.S. officials have acknowledged losing the surveillance drone. They have said Iran will find it hard to exploit any data and technology aboard it because of measures taken to limit the intelligence value of drones operating over hostile territory.
Hajizadeh said the drone contained many "secret codes," but he implied that these had been cracked, saying the spy plane now had "no hidden points."
He said exact information about the drone's history had been recovered indicating that it had flown "above [al-Qaida leader Osama] bin Laden's Pakistani hideout two weeks before he was assassinated."
The Washington Post reported two weeks ago that a CIA stealth surveillance drone flew deep over Iranian territory more than three years ago, capturing images of a secret uranium enrichment facility near Qum before returning home.
The newspaper, quoting former senior U.S. intelligence officials, said there was no sign the aircraft was ever detected. It said such CIA spy planes scoured dozens of suspicious sites related to Iran's disputed nuclear program before the RQ-170 aircraft crashed in December.
Western countries say Iran's nuclear program aims to produce atomic weapons. Iran says the work is solely for peaceful purposes.