Trump speech violated Iran nuclear deal: Zarif
Trump's virulent speech contravened three articles of the 2015 deal, Zarif said in televised remarks broadcast late on Saturday.
They include the requirement to implement the accord "in good faith" and for the US to "refrain from re-introducing or re-imposing" sanctions related to Iran's nuclear programme.
"I have already written nine letters (to EU foreign policy chief Federica Mogherini) listing the cases where the United States has failed to act on or delayed its commitments under the JCPOA," Zarif said, using the technical name for the nuclear deal.
Mogherini helped negotiate the nuclear deal alongside the US, Britain, France, Germany, China and Russia.
Zarif said he would write a new letter regarding Trump's speech last Friday, and warned of a "reciprocal measure" if sanctions were reimposed.
In his speech, Trump refused to "certify" the nuclear deal and warned he would "terminate" the deal unless Congress introduced tough new sanctions against Iran's missile and nuclear programmes, as well as its "destabilising" activities in the Middle East.
Zarif responded by saying: "Our achievements in the field of ballistics are in no way negotiable.
"We live in a region into which hundreds of billions of dollars of lethal American weapons have poured, turning it into a gunpowder storehouse... so we have the right to have defensive means," he said.
The protocol allows unannounced inspections by the UN nuclear watchdog, the International Atomic Energy Agency (IAEA). Iran agreed to implement it as part of the nuclear deal, without turning it into law.