US sanctions on Iran having 'major effect': NSA Bolton says

The Trump administration's unilateral reimposition of crippling sanctions on Iran was already having a "major effect" with the oil-rich Gulf nation witnessing anti-regime demonstrations and even riots, US National Security adviser John Bolton has claimed.

The Trump administration announced on Monday that it would reimpose US sanctions on Iran following President Donald Trump's decision in May to quit the 2015 landmark nuclear agreement with Tehran forged under former President Barack Obama's tenure.

Under that deal, Iran agreed to limit its uranium enrichment programme in return for the lifting of crippling Western sanctions.

Trump argues that the deal will not prevent Iran from finding ways to develop nuclear weapons. Iran has always insisted that its nuclear research was for civilian purposes.

"Right up until the present day, we've seen continued demonstrations, even riots in cities and towns, all across Iran as the economic situation worsens," Bolton told CNN.

"So I think our reimposition of sanctions has already had a major effect," Bolton, the Trump administration's foreign policy hawk, said.

Bolton said that the US was seeking to put "unprecedented pressure" on Iran and that members of the administration had been speaking to their European counterparts in an effort to sway them to reimpose sanctions on Iran as well despite the nuclear accord.

"We've been, in the last three months since the President announced his intention to get out of the nuclear deal, we've been in near constant communication with our friends in Europe and around the world urging them to join us," Bolton said.

The Joint Comprehensive Plan of Action (JCPOA) agreement by the US along with the European Union, UK, France, Germany, Russia and China with Iran set up an arrangement for confirmation that Iran would not develop nuclear weapons capabilities in exchange for the lifting of an international sanctions regime against Iran.

The European nations said in a statement that they "deeply regret" the US move and that the nuclear agreement "is working and delivering on its goal."