LONDON: Donald Trump will regret it if he pulls out of the nuclear deal with Iran, President Hassan Rouhani said on Monday, warning the US president that the Iranian response would be stronger than he thinks.

US sanctions that were lifted under the Joint Comprehensive Plan of Action (JCPOA) signed in 2015 will resume unless Trump again waives them on May 12. Trump has effectively set that as a deadline for European powers to "fix the terrible flaws" of the deal.

Rouhani said in a speech broadcast live on state television:

"The new US president - who has big claims and many ups and downs in his words and actions - has been trying for 15 months to break the JCPOA ... but the structure of the JCPOA is so strong that it has not been shaken by such quakes.

"Iran will not violate the nuclear deal, but if the United States withdraws from the deal, they will surely regret it. Our response will be stronger than what they imagine and they would see that within a week."

Iran has warned that it would ramp up its nuclear programme if the JCOPA collapses, to achieve a more advanced level than before the deal.

Rouhani was speaking as Tehran marked National Nuclear Technology Day and unveiled what it said were its latest nuclear achievements including a nuclear battery and centrifuges for the oil industry.

France, Britain and Germany are seeking to persuade their EU partners to back new sanctions on Iran, mainly on its missile programme, as a way to persuade Trump to stick with the nuclear deal that put curbs on Iran's nuclear activities in return for sanctions relief.