Iranian president Hassan Rouhani said the United States would regret if they pulled out of the Iranian nuclear program, Press TV reported.

“If the deal breaks, they will surely regret it. They will witness the fallout in less than a week,” Rouhani said on Monday during a special ceremony held on National Nuclear Technology Day.

Back in January U.S. President Donald Trump warned he would pull out of the deal if the European countries fail to fix the flaws of the agreement.