President Donald Trump responded to a threat from Iran’s President Hassan Rouhani, issued on Sunday, vowing to make the country suffer consequences if threats continue.

“NEVER, EVER THREATEN THE UNITED STATES AGAIN OR YOU WILL SUFFER CONSEQUENCES THE LIKES OF WHICH FEW THROUGHOUT HISTORY HAVE EVER SUFFERED BEFORE,” President Trump wrote in all-caps on Twitter. “WE ARE NO LONGER A COUNTRY THAT WILL STAND FOR YOUR DEMENTED WORDS OF VIOLENCE & DEATH. BE CAUTIOUS!”

Rouhani delivered his threat during a speech to Iranian diplomats.

“Mr. Trump, don’t play with the lion’s tail, this would only lead to regret,” he said, warning that “war with Iran is the mother of all wars.”

Rouhani made his remarks in response to reports that the Trump administration was trying to disrupt the current government in Iran.