Iran today condemned new sanctions adopted by the US Senate and vowed to respond with "reciprocal and adequate measures".
Tehran "will take reciprocal and adequate measures to guarantee its national interests", foreign ministry spokesman Bahram Ghassemi said, quoted by ISNA news agency.
He did not elaborate.
The Senate on Thursday overwhelmingly passed tough sanctions on Iran for its alleged "continued support of terrorism" and the bill has been sent to the House of Representatives for approval.
The new restrictions impose mandatory sanctions on people involved with the Islamic republic's ballistic missile programme and those that transact with them.
It also applies terrorism-related sanctions to the Islamic Revolutionary Guard Corps, and re-enforces aspects of the arms embargo on Iran.
Ghassemi retorted that the measure against Iran's ballistic missile programme was "totally illegal and illegitimate".
"Iran's armed forces will continue to defend the country's security and interests," the foreign ministry spokesman said. "Iran's ballistic programme is totally legitimate."
There continues to be strong resistance in Washington to the 2015 nuclear deal Iran signed with world powers, with many lawmakers still unhappy with the deal.