The fevered partisanship of US politics is damaging the country's foreign policy, Iran said Saturday, hitting out at threats of military action against it should nuclear diplomacy ultimately fail.
The comments in Tehran came after US President Barack Obama said in a letter that all options remain on the table against Iran.
Iran and six world powers led by the US struck a deal last month on Tehran's disputed nuclear programme but it is undergoing a bruising review in Congress and has yet to be implemented.
"Political partisanship and competition have taken US foreign policy hostage," foreign ministry spokeswoman Marzieh Afkham said, calling Obama's remarks "repetitive and baseless".
These claims are "showing the uncertainty and depth of confusion of American officials in determining their national interests," Afkham said, according to the official IRNA news agency.
The US president said in a letter to Jerrold Nadler, a Democrat who has announced his support for the deal, that the agreement is good for America, Israel and the Middle East in general.
"We have a wide array of unilateral and multilateral responses that we can employ if Iran fails to meet its commitments," Obama said.
"All of the options available to the United States -- including the military option -- will remain available through the life of the deal and beyond," he added.
Israel, which Iran does not recognise as a state, has been the biggest opponent of the nuclear deal, claiming that it paves the way to Tehran obtaining a nuclear bomb.
Obama has said the deal does precisely the opposite, and Iran denies seeking an atomic weapon.
If Congress chooses to reject the deal, Obama will still be able to veto the move as long as Republicans fail to obtain a two thirds majority against it.