Iran said Saturday that the 2015 nuclear deal with the United States and other key world powers “cannot be renegotiated in any way,” rejecting President Trump’s threat to pull out of the agreement if the other parties do not fix its “disastrous flaws.”

Trump, after months of railing against the agreement, signed a waiver on Friday keeping the deal in place for at least 90 days but called for changes, particularly removal of so-called “sunset clauses” that allow Iran to gradually resume advanced nuclear activities in the next decade. .

“Despite my strong inclination, I have not yet withdrawn the United States from the Iran nuclear deal,” Trump said in a statement, warning that the options were to fix “the deal’s disastrous flaws, or the United States will withdraw.”

“This is a last chance,” he added.

Britain, France and Germany had called on Trump on Thursday to uphold the pact.

Iran’s foreign ministry in a statement ruled out any renegotiation of the terms, saying it “will not accept any changes in this agreement now or in the future” nor allow it to be linked to any other issue.

The deal, known as the Joint Comprehensive Plan of Action, was reached in 2015 among Iran, the five permanent members of the U.N. Security Council (China, France, Russia, United Kingdom and United States) plus Germany and the European Union.

Under its terms, economic sanctions against Iran were to be lifted in exchange for Tehran halting uranium enrichment.

Trump also wants to make Iran’s long-range missile program subject to sanctions under the agreement. The deal, negotiated by the Obama administration is centered solely on the Iranian’s nuclear weapons program.

The foreign ministry noted in an earlier note Saturday on its website that the agreement  is “not a bilateral agreement that can be…