The House of Representatives has passed a measure that would block US aircraft sales to Iran, potentially undercutting a Boeing deal with Tehran worth up to $25 billion.
Two amendments approved to an appropriations bill from Representative Peter Roskam would ban sales from Boeing and from European rival Airbus, amid concerns the aircraft could be used for military purposes, the congressman said in a statement Friday.
One amendment would prohibit the Office of Foreign Assets Control from using funds to authorize a license necessary to allow aircraft to be sold to Iran. A second would bar loans from US financial institutions to purchase militarily adaptable aircraft.
The ban would need to be approved by the Senate or any bill that reconciles differences in legislation by the two chambers.
Roskam, an Illinois Republican, said in a tweet that in the vote Thursday, "House Democrats did not mount any significant opposition and, in many cases, joined efforts to block the sale."
The news comes weeks after Boeing and Iran Air confirmed a tentative deal for the sale of passenger planes, described as a landmark for normalizing the difficult US-Iran relationship.
The deal, valued at up to $25 billion, would be the largest between a US business and Iran since the 1979 Islamic revolution.
Boeing said it had reached a preliminary agreement with the state-owned carrier.
The Islamic republic had been an international pariah prior to a nuclear deal reached last year, and the US still has some sanctions in place against Iran.
But a spokesman for the Iranian foreign ministry on Friday said the measure was "incompatible" with the accord, under which Washington was to lift economic sanctions in exchange for Tehran curbing its nuclear activities.
"We have nothing to do with US internal affairs," Bahram Ghasemi said, quoted by the official IRNA news agency.
"We consider the government of the United States to be responsible for implementing the country's commitments" under the accord.
Boeing archrival Airbus in January reached a deal to sell Iran 118 aircraft.
French officials in April said the transaction was in the final stages of winning approval from the US Office of Foreign Assets Control, a key hurdle, because some of the aircraft components are made in the US.
Roskam and some other lawmakers have opposed deals with Iran, asserting that Tehran remains a supporter of violent jihadists around the world.
"If you wouldn't do business with Islamic State, you shouldn't do business with the Islamic Republic," he said in an April opinion piece in the Wall Street Journal.