Iran's parliament has voted in favour of boosting investment in its missile defence and foreign operations programmes by more than $500m (£386m).
The bill, which received overwhelming approval, is in response to the latest round of US sanctions against Tehran.
The US imposed sanctions after a ballistic missile test in January.
Tehran says this violates the 2015 nuclear deal, which US President Donald Trump has called "the worst ever" and threatened to tear up.
The Iranian legislation must pass a second vote before submission for final approval.
Iranian MPs shouted "death to America" after Speaker Ali Larijani announced the result of the vote.
Of the members present, 240 parliamentarians out of 244 voted in favour of passing the bill.
It proposes that the government allocates an additional $260m for the "development of the missile programme" and the same amount to Iran's Quds Force, a branch of the country's Revolutionary Guards Corps, the official state news agency Irna said.
Mr Larijani said the move was meant to counter Washington's "terrorist and adventurist activities" in the Middle East, AFP news agency reports.
The 27-point bill will also impose sanctions on US military and intelligence officials in the region.
Iran's chief nuclear negotiator, Abbas Araqchi, said the new bill was not in violation of the 2015 agreement limiting the country's nuclear programme.
The nuclear deal, between Iran and six world powers including China, Russia and the UK, is largely seen as the best way to prevent Iran getting a nuclear weapon.
The agreement saw crippling economic sanctions on Iran lifted in return for the country restricting its sensitive nuclear activities.
Mr Trump has recently backed away from his key campaign promise to withdraw from the nuclear agreement.
Last week, Iranian President Hassan Rouhani warned Mr Trump that he risks political suicide if he scrapped the nuclear deal with Tehran.