The US is "afraid" of war with Iran, the head of Iran's Revolutionary Guard said as tensions between Tehran and Washington intensified over the weekend.
Major General Hossein Salami told the Iranian state news agency, IRNA, that the country does not want war.
"The difference between us and them is that they are afraid of war and don't have the will for it," he said.
His remarks came against a backdrop of increased volatility in the region, with the US sending an aircraft carrier strike group to the Persian Gulf to counter an unspecified threat from Iran.
Major General Salami's comments were dismissed by the US president on Twitter. "If Iran wants to fight, that will be the official end of Iran. Never threaten the United States again!" Mr Trump tweeted.
The US Federal Aviation Administration has urged commercial aircraft to exercise caution when flying over the Persian Gulf, warning they ran the risk of being "misidentified".
A similar misunderstanding in 1988 led to an American warship bringing down an Iran Air flight, killing all 290 people on board.
Iraq, meanwhile, has condemned as "political" a decision by US energy giant ExxonMobil to evacuate staff from a southern oil field after Washington ordered personnel to quit its Baghdad embassy.
Saudi Arabia responded to the escalating crisis by calling for a Gulf summit, adding that while the country did not want war it would defend itself if hostilities erupted.
"The kingdom of Saudi Arabia does not want a war in the region nor does it seek that," Minister of State for Foreign Affairs Adel al-Jubeir told a news conference on Sunday.
"It will do what it can to prevent this war and at the same time it reaffirms that in the event the other side chooses war, the kingdom will respond with all force and determination, and it will defend itself and its interests."
In Washington Donald Trump has emerged as a dove within his own administration, telling his acting defence secretary, Patrick Shanahan, that he wants to avoid an armed conflict erupting.
It has put the US president at odds with John Bolton, his national security adviser and a long-standing foreign policy hawk, who has made little secret of his desire for regime change in Tehran.
Secretary of State, Mike Pompeo, has also sought to lower the temperature by asking European allies to intervene with Iran.
Washington's stance on Iran has put it at odds with European allies, notably after it withdrew from the nuclear deal negotiated by the Obama administration.
Over the weekend Tulsi Gabbard, an Iraq war veteran and Democratic presidential candidate, rounded on Mr Trump and Mr Pompeo accusing them of leading the country into a war with Iran.
"He says he doesn't want it, but the actions of him and his administration, people like John Bolton and Mike Pompeo, tell us a very different story," she said on ABC.
"They are setting the stage for a war with Iran that would prove to be far more costly, far more devastating and dangerous than anything that we saw in the Iraq war."