An Iranian flag is pictured at the United Nations headquarters in New York, Jan. 8, 2020. (Xinhua/Li Muzi)

US President Donald Trump vowed Saturday to use a controversial technique to unilaterally reinstate UN sanctions on Tehran, a move with huge repercussions for the Iran nuclear deal.

His declaration came a day after the UN Security Council overwhelmingly rejected a US resolution to extend an Iranian arms embargo.

"We'll be doing a snapback," Trump said during a news conference at his New Jersey golf club. "You'll be watching it next week."

The president was referring to the contested argument that the US remains a "participant" in the 2015 Iran nuclear deal - despite Trump's withdrawal from it - and therefore can force a return to sanctions if it sees Iran as being in violation of its terms.

Iranian President Hassan Rouhani said the US had failed to kill off what he called the "half alive" deal with major powers that gave Iran relief from sanctions in exchange for curbs on its nuclear program.

"The United States failed in this conspiracy with humiliation," said Rouhani.

"This day will go down in the history of our Iran and in the history of fighting global arrogance."

Only two of the Council's 15 members voted in favor of the US resolution seeking to extend the embargo, highlighting the division between Washington and its European allies since Trump withdrew from the nuclear accord in 2018.

The Europeans on the Council all abstained, and Iran mocked the Trump administration for winning the support of just one other country, the Dominican Republic.

European allies have been skeptical on whether Washington can force sanctions, with experts saying a "snapback" threatens to plunge the Council into one of its worst-ever diplomatic crises.

Trump also said Saturday he would "probably not" take part in a summit proposed by Russian President Vladimir Putin on addressing the situation.

Putin had appealed to China, France, Britain, the US, Germany and Iran to convene an emergency video summit to avoid an escalation of tensions in the Gulf.

US Secretary of State Mike Pompeo, in a visit to Poland on Saturday, made it clear the US would press on.

AFP