The US has suspended sales of all spare parts from the retired F-14 fighter jet over concerns they could end up in Iran, the defence department said.
The US retired its F-14 fighter jet fleet last year
Officials said sales were halted on 26 January and would remain frozen pending a "comprehensive review".
Iran bought a fleet of F-14s from the US in the 1970s and is the only country still flying the jets.
The move comes amid congressional concern that Iran is gaining access to sensitive aircraft parts.
'Defies common sense'
The US no longer uses the F-14 fighter, an aircraft made famous in the 1980s film Top Gun.
Until last week it had been selling off non-sensitive spare parts to the public via its Defense Logistics Agency.
DLA spokeswoman Dawn Dearden said that the freeze covered all F-14 parts and was in place "given the current situation in Iran".
The US sold 79 F-14s to Iran before the overthrow of the Shah in 1979, when the two countries were allies.
Democrat Senator Ron Wyden, who is introducing legislation aimed at banning the sale of all F-14 parts, said selling the surplus was not in US interests.
"It just defies common sense to be making this kind of equipment available to the Iranians with all that they have done that is against our interests," he said on Monday.
There has also been congressional concern that lapses in security have allowed the sale of sensitive items to overseas buyers.
The decision comes at a time of rising tension between Iran and the US over Tehran's nuclear programme.
Washington says Iran is seeking to acquire weapons, but Iran says the programme is for peaceful uses only.