Iranian President Hassan Rouhani blasted the Trump administration Friday for moving "unilaterally" against the 2015 nuclear deal, denouncing the new U.S. policy but stopping short of announcing a withdrawal from the pact.

“We will continue to stick to the deal and to cooperate with the [International Atomic Energy Agency] within the framework of international law,” he said, referring to the watchdog tasked with monitoring Iran’s nuclear program. But if the deal’s other signatories “refuse to abide by their commitments, Iran will not hesitate” to respond, he said.

Rouhani’s remarks came just hours after Trump announced his intention to “decertify” the deal in a report to Congress. The agreement, which was negotiated under the Obama administration, curbed Iran’s nuclear activities in exchange for major sanctions relief.

Trump hopes congressional leaders will ramp up pressure on Iran by legislating new restrictions on some of the deal’s provisions. Iran, Trump said, is “under the control of a fanatical regime.”

In his address, which was carried live on state television, Rouhani fired back, saying that the United States is "more isolated than ever."

“The speech tonight showed that the [nuclear deal] is much stronger than what this gentleman thought during the presidential campaign,” he said, referring to Trump. Rouhani, a moderate leader who has pushed for Iran to open up to the world, was reelected for a second term in May.

“This is an international, multilateral deal,” Rouhani said of the agreement, also known as the Joint Comprehensive Plan of Action, or JCPOA. “It is not a document between Iran and the United States that he can treat the way that he likes.”

In his policy speech Friday, Trump referred to Iran as a "dictatorship" with a "long campaign of bloodshed."

"The regime remains the world's leading state sponsor of terrorism," he said, adding that he would order the Treasury Department to designate Iran's Revolutionary Guard Corps a supporter of terrorism.

The Revolutionary Guard is an official branch of Iran’s armed forces, although it commands proxy forces in the region and wields vast political and economic influence. Trump’s move, using an existing executive order on terrorism financing, falls short of the Foreign Terrorist Organization designation used by the State Department, which carries much harsher sanctions.

Still, the designation could have far-reaching consequences, both in Iran and the region. The Revolutionary Guard, which maintains land, sea and air forces, has threatened U.S. military bases in the Persian Gulf. Iran’s Foreign Ministry said Friday that designating the Revolutionary Guard a terrorist group would provoke an unspecified “crushing” response.

The Revolutionary Guard “is a powerful force that is popular among the Iranian people,” Rouhani said. In recent months, Rouhani sought to curb the Revolutionary Guard’s role in a stagnant economy as part of a bid to woo further foreign investment.

A woman looks at pictures of President Trump as she follows the news on her mobile phone in Tehran on Oct. 13, 2017. (Tima Agency/Reuters)

But now, Rouhani said, Iran is united in the face of foreign aggression.

“You made us more united than ever,” he said, addressing the United States. “You can try to separate the government and the people, but you cannot sow discord.”

“The Iranian nation is not a nation that will easily retreat in the face of a dictator,” he said.

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