Iran's foreign minister said Sunday demanded Washington stick to the recently agreed nuclear deal between Tehran and major powers once implementation begins, and block any attempt by lawmakers to change it.
The comments by Mohammad Javad Zarif came after President Barack Obama's Democrats last week staved off a united Republican effort to sink the July agreement in Congress.
"We hold the US government accountable for the implementation of the JCPOA," Zarif told a press conference in Tehran, referring to the Joint Comprehensive Plan of Action agreed with the six powers, including Washington.
"In our view, any measures in violation of JCPOA by Congress should be stopped by the United States government," he said.
"This government, as well as future US governments, is obliged to implement JCPOA, in case it is implemented."
Republican lawmakers have vowed to press on with their campaign to torpedo the deal despite Thursday's blocking vote in the Senate.
They have threatened legal action against the administration, claiming that by failing to provide lawmakers with the texts of what they call "side deals" – confidential inspection protocols negotiated between Tehran and the UN nuclear watchdog – it breached its obligations to Congress.
The deal has been roundly criticized both in the US and abroad – particularly by Israel and Sunni Arab gulf states – for ending all sanctions in return for relatively minor concessions by Tehran, which even if kept to would only delay a nuclear weapons program by 10-15 years.
Zarif's comments come a day after Iran revealed it "discovered" a "surprising" amount of uranium reserves in its own mines – far greater than estimates by western officials.
AFP contributed to this report.