TEHRAN: Iran's supreme leader Ayatollah Ali Khamenei on Wednesday dismissed US President Donald Trump´s aggressive criticism as "rants and whoppers" while vowing that Tehran would stick to its nuclear commitments.

"I don't want to waste my time on answering the rants and whoppers of the brute US president," Khamenei said in a speech to students in Tehran, published on his Telegram channel.

It was his first response to Trump's bellicose speech last Friday in which he called for tougher sanctions to curb Iran´s "destabilising activities" in the Middle East.

"They are angry as today the Islamic Republic of Iran has disrupted their plans in Lebanon, Syria and Iraq," Khamenei said.

"Everyone be assured that this time, too, America will be slapped and defeated by the nation of Iran."

Khamenei said the world should not be fooled by Trump's public persona.

"The US president displays stupidity, but this should not cause us to ignore America´s mischief," he said.

He said Iran would stick by its commitments under the 2015 nuclear deal, which Trump has threatened to "terminate" unless the US Congress tightens sanctions on the country.

Khamenei welcomed Europe´s strong support for preserving the nuclear agreement but also urged it not to follow the same line as Washington.

He rejected suggestions, notably from French President Emmanuel Macron, that more negotiations were needed on Iran's ballistic missile programme and regional operations.

Europe "must refrain from entering into our defence issues", Khamenei said.

"To ask the same thing (as the Americans) about why Iran is present in the region ? well, deal with it.

"Or to ask why Iran has missiles ? well, why do you have missiles? Why do you have nuclear weapons? We will not accept the Europeans going along with America´s bullying."