TEHRAN — Iran’s president lashed out at the United States on Monday as Iran marked ‘‘National Nuclear Day,’’ dedicated to its achievements in nuclear technology.

Hassan Rouhani said that despite many attempts, the United States has ‘‘failed to destroy’’ the 2015 deal between Iran and world powers. Rouhani also mocked President Trump, who has described the deal as bad. Trump extended sanctions waivers in January but has declined to re-certify the deal.

‘‘They spent huge amounts of dollars and talked a lot, and posted so many tweets, thinking that this building would shake with tweets,’’ Rouhani said of the United States.

The nuclear agreement curbed Tehran’s controversial nuclear enrichment program in exchange for relief from international sanctions.

Rouhani reaffirmed his government’s commitment to the deal and said Iran would not be the first to violate it. He also stressed Iran is ready to quickly revert to the situation before the deal should the United States abandon it.

A spokesman for Iran’s Atomic Agency said that should the deal collapse, Iran would be able to restart the enrichment program and enrich uranium to the level of 20 percent within two days. Weapons-grade uranium is 90 percent enriched.

ASSOCIATED PRESS