BEIRUT (Reuters) – The head of Iran’s Revolutionary Guards said on Wednesday that the United States should experience “painful responses” following President Donald Trump’s harsh criticism of Tehran at the United Nations.

In his first speech to the U.N. General Assembly on Tuesday Trump called Iran “a corrupt dictatorship” and accused it of supporting terrorism and destabilizing the Middle East. He also hinted he might not recertify a 2015 nuclear deal with Tehran when it comes up for a mid-Oct. deadline.

“Taking a definitive stand against Trump is only the beginning of the path,” said General Mohammad Ali Jafari, according to Sepah News, the news site of the Revolutionary Guards.

“What is strategically important is that America witnesses more painful responses in the actions, behavior and decisions that Iran takes in the coming months.”

In recent months, tensions have ramped up between Iran and the United States in the Gulf, with both sides accusing each other of provocative maneuvers with military vessels.

Jafari urged Iranian President Hassan Rouhani to deliver a definitive response to Trump in his speech at the United Nations on Wednesday.

“With the successive and exhausting defeats that the Americans have faced in the region from Iran, it’s natural that their nervous system and coherence of thought have fallen apart,” Sepah News quoted Jafari as saying.

In Tuesday’s speech, Trump called the 2015 nuclear deal, negotiated between Iran and six world powers, and backed by his predecessor Barack Obama, “an embarrassment”. Under the deal, Iran agreed to curb its atomic program in return for easing economic sanctions.

(Reporting By Babak Dehghanpisheh; Editing by Gareth Jones)