WASHINGTON – An Iranian scientist who defected to the United States returned home amid an escalating propaganda war between Tehran and Washington but without $5 million he was paid for what a U.S. official said was “significant” information about his country’s nuclear programs.

The CIA paid Shahram Amiri a total of $5 million to provide intelligence, but Amiri did not take the money with him, the U.S. official said Thursday. The funds were barred by U.S. Treasury sanctions that prohibit the flow of American dollars to Iran.

“Anything he got is now beyond his reach, thanks to the financial sanctions on Iran,” said the U.S. official, who spoke on condition of anonymity. “He’s gone, but the money’s still here.”

The official said Amiri provided the CIA with “significant, original information” that the agency was able to independently verify, although he would not detail the scope of the intelligence. There was also no indication, the official said, that Amiri might have been a double agent sent by the Iranians to learn what the CIA knows about its suspected nuclear weapons program.

Still, several former American intelligence officers said Thursday that Iranian intelligence officials would be expected to debrief Amiri to try to learn every last detail about the exchanges that took place between him and his CIA handlers — a process that could take weeks or even months.

The former officers, who also spoke on condition of anonymity, said Iranian intelligence would try to exploit any information to hunt for existing American spies.

Iran’s leaders are expected to use Amiri to ring up as many propaganda points as possible against Washington, and within hours of the former defector’s arrival in Tehran, the war of words heated up.

Iranian officials touted Amiri’s claim he had been abducted by U.S. agents, while a State Department official parried with a call for three long-imprisoned American hikers to be released and treated similarly to Amiri, who they said was allowed to return to his homeland.