Iranian President Hassan Rouhani reiterated Wednesday that for Tehran, the 2015 six-party agreement is non-negotiable, and will collapse if European powers succumb to U.S. pressure to demand even greater restrictions on Iranian security forces.

"It's all or nothing. The JCPOA is not correctable or renegotiable," Rouhani said at a news conference in Tabriz, referring to the Iran nuclear moratorium agreement by the acronym for its formal name, the Joint Comprehensive Plan of Action.

"If the JCPOA is destroyed, everyone should say farewell to it," said Rouhani, speaking a day after a summit ended in Washington between U.S. President Donald Trump, who has threatened to withdraw the United States from the pact, and French President Emmanuel Macron, who tried to persuade Trump to maintain the agreement.

Under the 2015 pact, Tehran agreed to actions to prevent it from developing nuclear weapons in return for the lifting of crippling financial sanctions.

Trump has threatened to withdraw the United States from the deal also negotiated by Britain, China, France, Germany, Russia and the European Union, if an agreement to revamp it cannot be reached by May 12.

"I talked with President Macron several time and I stressed that it's not possible to add any single sentence to the JCPOA or remove a sentence from it and Macron agreed," Rouhani said.

Rouhani's remarks follow a joint press conference in Washington on Tuesday, at which both Macron and Trump criticized Iran for developing missiles and its involvement in conflicts throughout the Middle East and Persian Gulf, and raised the possibility of pounding out a new deal with Iran.

Macron said he spoke to Trump about a "new deal" which would address outstanding U.S. and European concerns regarding not only Iran's nuclear program, but other security matters as well.

At the joint press conference, Trump again called the Iran nuclear deal a "terrible deal" that was "insane" and "ridiculous" because it did not deal with Iran's ballistic missiles or Iran's involvement in conflicts in Yemen, Syria and elsewhere. "We made this terrible deal but we're going to discuss it," Trump said.

In separate comments that Rouhani made Wednesday while opening a tourism exhibition in Tabriz, Iran's president said the United States ought to uphold its own commitments under the existing six-party agreement before demanding changes.

The United States pledged to fulfill certain commitments in the 2015 pact. But Washington has violated the deal by threatening banks throughout the world and investors if they do business with Iran, Rouhani said in separate comments to Iranian officials and foreign guests.

"You have a debt to us over the (existing) nuclear deal. First settle your debt, then talk about the future," Rouhani said.

Referring to the U.S. leader's previous business career as a property developer and wheeler-dealer, Rouhani described Trump as a "trader and tower maker" with a poor understanding of international law and global affairs.

He then posed a series of rhetorical questions concerning the 2015 pact and the U.S. leader's assessment of it.

"If the nuclear deal was bad and dangerous, why did your predecessor sign it? Only you can distinguish bad and good?"

Tehran has said it will withdraw either from the nuclear deal or from the Treaty on the Non-Proliferation of Nuclear Weapons, and restart uranium enrichment at a higher level, if Washington withdraws from the agreement.

Iranian foreign minister Javad Zarif told the Associated Press on Tuesday that it's likely Iran will abandon the six-party deal in retaliation if the United States withdraws. But Supreme National Security Council secretary Admiral Ali Shamkhani told reporters in Tehran the same day that withdrawing from the NPT, a landmark agreement signed by 191 nations, is more likely.

Trump warned Iran at the joint news conference Tuesday with Macron about restarting uranium enrichment, saying: "If they restart their nuclear program, they will have bigger problems than they have ever had before."