"The Iranian nation has stood firmly and any wrong move by the hegemonic system on the JCPOA will draw a reaction from the Islamic Republic", the Leader said at a graduation ceremony of Iran's police cadets in Tehran on Sunday.
Khamenei's remarks come after the recent statement of US President Donald Trump, who accused the Islamic Republic of violating the nuclear deal's "spirit".
During the negotiations with the world powers in 2013-15, "the country's officials reached the conclusion that they should negotiate and ignore some of their rights so that sanctions would be removed", he said.
The Leader of the Revolution went on to say: Today we witness, despite all the contracts, deals, and multiple talks regarding the JCPOA, the attitudes of the U.S. towards the negotiations and their outcomes are totally oppressive, hounding, and cruel.
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Iranian Supreme Leader Ali Khamenei threatened Washington on Sunday, saying: "Iran will respond to every wrong step by the United States regarding the nuclear deal".
On regional issues, he noted that the reasons behind insecurity in the Middle East can be traced to the "wicked and mischievous interventions" by the US. Nevertheless, US officials stated that Washington will announce the continuation of sanctions relief for Iran in accordance with the deal.
The global agreement is facing a serious threat of collapse as tensions mounted between Washington and Tehran recently.
Since the historic deal was signed in Vienna, the IAEA has repeatedly confirmed the Islamic Republic's compliance with its commitments under the JCPOA, but some other parties, especially the USA, have failed to live up to their undertakings.