Washington extended sanctions relief for Iran on Thursday but said it had yet to decide whether it would maintain the 2015 nuclear deal
Iran would react strongly to any "wrong move" by the United States on Tehran's nuclear deal, Supreme Leader Ayatollah Ali Khamenei said, after President Donald Trump accused Iran of violating the "spirit" of the agreement.
"The Iranian nation is standing firm and any wrong move by the domineering regime regarding the [nuclear accord] will face the reaction of the Islamic Republic," state television quoted Ayatollah Khamenei as saying on Sunday.
Washington extended some sanctions relief for Iran on Thursday under Tehran's 2015 deal with world powers but said it had yet to decide whether to maintain the agreement.
Trump, who must make a decision by mid-October, said Iran was violating "the spirit" of the deal under which it got sanctions relief in return for curbing its nuclear programme.
"Today, despite all the commitments and discussions in the negotiations, America's attitude towards these negotiations and their outcome is completely unjust and amounts to bullying," Khamenei said.
"The Americans should know that the Iranian people will stand firm on their honourable positions and on important issues related to national interests, there will be no retreat by the Islamic Republic," Khamenei said in a speech to Iranian military academy graduates.
Iran said last month it could abandon the nuclear agreement "within hours" if the United States imposes any new penalties, after Washington ordered sanctions over Tehran's ballistic missile tests.
The United States imposed unilateral sanctions after saying the missile tests violated a UN resolution, which endorsed the nuclear deal and called upon Tehran not to undertake activities related to ballistic missiles capable of delivering nuclear weapons, including launches using such technology.