The speaker of Iran’s parliament has offered a particularly scathing review of US President Donald Trump’s decision to pull the US out of the Iran nuclear deal, saying Trump does not have the “mental capacity” for his job.

Trump announced that he was withdrawing the United States from the landmark deal on Tuesday, sparking an avalanche of criticism from both sides of the political divide in America and also upsetting the international community, including US allies and Russia.

The speaker of Iran’s parliament, Ali Larijani, took a particularly dim view of the decision telling the Iranian assembly that: "Trump does not have the mental capacity to deal with issues.”

"Trump's abandoning of the nuclear deal was a diplomatic show… Iran has no obligation to honour its commitments under the current situation,” Larijani said. "It is obvious that Trump only understands the language of force.”

Members of parliament also chanted “Death to America,” and burned a US flag and a symbolic copy of the nuclear pact, known officially as the Joint Comprehensive Plan of Action (JCPOA), Reuters reports.

President Hassan Rouhani said Iran would remain committed to the deal despite Washington's decision to withdraw from it. “If we achieve the deal's goals in cooperation with other members of the deal, it will remain in place... By exiting the deal, America has officially undermined its commitment to an international treaty,” Rouhani said in a televised speech.

Rouhani added that he has ordered the foreign ministry to negotiate with European countries, China, and Russia in coming weeks. “If at the end of this short period we conclude that we can fully benefit from the JCPOA with the cooperation of all countries, the deal would remain,” he said.