President Donald Trump has said that Iran is "playing with fire" after Tehran announced it has exceeded its limit for low-enriched uranium allowed under a 2015 nuclear deal with world powers.

"They know what they're doing. They know what they're playing with and I think they're playing with fire," Trump told reporters at the White House when asked if he had a message for Iran.

In Tehran, Iran's Foreign Minister Javad Zarif expressed exasperation over a White House statement that said there was "little doubt that even before the deal's existence, Iran was violating its terms."

Replying to the July 1 White House statement, Zarif wrote on Twitter: "Seriously?"

The United States withdrew from the nuclear deal in 2018 and reimposed sanctions on Iran's oil exports and other sectors.

Tehran has sought to pressure the remaining parties to save the deal, but announced on May 8 it would no longer respect the limit set on its enriched uranium and heavy water stockpiles.

U.S. Secretary of State Mike Pompeo called on July 1 for Iran to halt all uranium enrichment, saying "no nuclear deal should ever allow the Iranian regime to enrich uranium at any level."

"The United States is committed to negotiating a new and comprehensive deal with the Iranian regime to resolve its threats to international peace and security, " Pompeo said in a statement. "As long as Iran continues to reject diplomacy and expand its nuclear program, the economic pressure and diplomatic isolation will intensify."

"The Trump Administration calls on the international community to restore the longstanding nonproliferation standard of no enrichment for Iran's nuclear program," Pompeo said. "Iran has the uncontested ability to pursue peaceful nuclear energy without domestic enrichment.

Earlier on July 1, the International Atomic Energy Agency (IAEA) verified Iran's claim that it has exceeded the low-enriched uranium limit in response to the U.S. withdrawal from the 2015 nuclear deal.