President Donald Trump reacted Monday to the news that Iran had breached the limits on enriched uranium set by the Iran Nuclear deal.

“They know what they’re doing, they know what they’re playing with, and I think they’re playing with fire,” Trump said.

The president spoke to reporters briefly about Iran on Monday in the Oval Office after Iran announced their newly acquired nuclear material.

The White House also condemned Iran’s decision in a statement sent to reporters.

“It was a mistake under the Iran nuclear deal to allow Iran to enrich uranium at any level,” the statement read. “There is little doubt that even before the deal’s existence, Iran was violating its terms.”

The Trump administration vowed to continue holding Iran accountable and keep them from building a nuclear weapon.

“The United States and its allies will never allow Iran to develop nuclear weapons,” the statement read.