TEHRAN - Russia’s permanent representative to the Vienna-based international organizations says Iran may react even tougher than before if the United States makes the mistake of leaving the 2015 nuclear agreement again after a revitalization of the agreement, Press TV reported.

The U.S. nixed the Joint Comprehensive Plan of Action (JCPOA), the common name for the 2015 nuclear deal, in May 2018 under former President Donald Trump’s administration. The U.S. slapped the harshest sanctions intended to strangulate the Iranian economy.

“Many followers ask if there is a guarantee that US wouldn’t leave #JCPOA after its restoration,” Mikhail Ulyanov wrote in a tweet on Thursday.

Ulyanov added, “To my mind the best guarantee is extremely negative experience of the past. If #US repeats the previous mistake #Iran may decide to reciprocate even tougher. Nobody would like it.”

Reminded by a user that the plan to prevent such a move didn’t work the first time, Ulyanov gave an affirmative response, saying the international community is now aware of the “catastrophic results” of Washington’s so-called “maximum pressure” against Tehran, which persuaded Iran advance its nuclear program beyond what agreed in the JCPOA.

One year after the U.S. left the JCPOA Iran started to gradually remove bans on its nuclear activities. Late last year Iran started to enrich uranium to a purity of 20 percent, much higher than the 36.7 percent set by the JCPOA. In retaliation to a sabotage attack on the Natanz nuclear facility in April which Iran blamed on Israel, the Atomic Energy Organization of Iran (AEOI) also upgraded its nuclear enrichment to 60 percent.

Top Iranian nuclear negotiator Abbas Araqchi has called on the Biden administration to ensure that withdrawal from the nuclear deal and the imposition of sanctions will not happen again.

“It is natural that one of our serious issues in these negotiations has been and is to ensure that what the U.S. administration has done to JCPOA is not repeated, and in this regard, we need to come up with guarantees that assure us what the previous administration did, i.e. the re-imposition of sanctions and the withdrawal from the JCPOA, will not happen again. This is our natural desire and of course, it is not possible for us to return to the JCPOA without such a guarantee,” Araqchi said after the sixth round of talks.

Ulyanov further noted that the June session of the International Atomic Energy Agency’s Board of Governors showed that the international community, including the U.S., is extremely unhappy with the current situation.

“This is the best (not absolute, of course) guarantee against its repetition,” added Ulyanov, who heads Russia’s delegation in the ongoing Vienna talks aimed at reviving the JCPOA.

Ulyanov’s remarks come days after the sixth round of the talks concluded on June 20, as negotiators for Iran and the P4+1 group of countries — Britain, France, Russia, China and Germany — decided to return to their respective capitals for consultations to overcome the remaining differences.

The sides to the talks have voiced optimism to reach an agreement in the near future on how to bring all original parties to the JCPOA – first and foremost the U.S. – back into compliance with the deal.

Iran says if the efforts fail to secure an agreement by the end of President Hassan Rouhani’s term in August, the new Iranian administration will be in charge of deciding the future of the negotiations.

“In case the other parties are ready, the [Rouhani] administration has no problem with concluding the talks, but if no deal is finalized for any reason by the end of the 12th administration’s legal term, then the 13th administration [of Ebrahim Raeisi] will be in charge of the negotiations and taking a decision about their details,” Ali Rabiei, spokesman for the outgoing Rouhani administration, told reporters at his weekly press briefing on Tuesday.

Asked on Twitter whether his remarks were “backroom advice” to Iran to take bolder measures in case of another U.S. withdrawal from the nuclear pact, Ulyanov responded in the negative, asserting that his prediction of Iran’s action was, rather, “an advice and a reminder to #US hardliners.”

Meanwhile, Iranian President-elect Raeisi has emphasized that the U.S. must return to full compliance with the JCPOA and fulfill its commitments under the accord in order for Iran to do the same.

“European countries and the United States must look and see what they have done to the JCPOA. The United States violated the JCPOA while European countries failed to comply with their obligations,” Raisi said last week during his first press conference after his landslide victory in the June 18 election.

The president-elect also said the Iranian nation is not satisfied with the JCPOA as it has failed to deliver on its promises, adding that his administration will not pursue attritional talks on the deal.