Iran warned the US on Sunday that abandoning the nuclear deal would be a "historic mistake," less than one week before President Donald Trump is set to make a decision on the pact.
In a televised speech, President Hassan Rouhani said Iran had plans for "whatever decision is made by Trump" and that "when it comes to weapons and defending our country, we will not negotiate with anybody."
His comments come days before the May 12 deadline for Trump to decide whether or not to continue waiving sanctions on Iran that were lifted under the deal, formally known as the Joint Comprehensive Plan of Action (JCPOA).
Under US law, the President has to re-certify the agreement every three months.
As part of the 2015 pact agreed by Trump's predecessor Barack Obama, some European countries and Russia and China Iran must reduce its uranium stockpile in return for international sanctions being lifted.
Trump has long been critical of the accord, just last month calling it "insane" and "ridiculous" during a state visit with French President and leading deal supporter Emmanuel Macron.
Newly-appointed Secretary of State Mike Pompeo gave a further indication that the US was set to leave the deal during a visit to Saudi Arabia last month, when he called Iran "the greatest sponsor of terrorism in the world." He also said the accord in its current form was not to the president's liking.
Meanwhile, Macron has been leading the European charge on preserving the deal, shoring up support from British Prime Minister Theresa May and German Chancellor Angela Merkel in a flurry of diplomatic phone calls, and again bringing up the issue during a visit to Australia last week.
UK Foreign Minister Boris Johnson is also set to fly to Washington this week in a last-ditch effort to bolster support for the deal.
During Sunday's televised address, Rouhani said that only three countries were against the deal the US, Israel and Saudi Arabia.
Rouhani also said that Iran would produce "as many facilities, weapons, missiles that are necessary for our country," adding that "it is none of others' business."
As the nuclear deadline approaches, Israeli Prime Minister Benjamin Netanyahu has attempted to dissuade Trump from renewing the deal, last week staging an eye-catching presentation claiming new evidence that Iran violated the agreement.
However, nonproliferation experts who spoke with CNN said Netanyahu provided no evidence that Iran contravened the terms of the agreement.
Amid these rising tensions between Israel and Iran, Netanyahu again weighed in on Sunday, saying it's "better now rather than later" for Israel to block "Iranian aggression" in the region.
Speaking at the weekly cabinet meeting, Netanyahu said Iran had in recent months been "transferring advanced weaponry in order to attack us, on the front lines and on the home front."
He described the weapons as "attack drones, surface-to-surface missiles and Iranian anti-aircraft systems that threaten Israeli Air Force aircraft."
"We are determined to block the Iranian aggression against us at its earliest stages, even if it takes a struggle," he said.