“I’ll be involved in those talks, indirectly. And they’ll be very important,” Trump told reporters aboard Air Force One.

Tensions are soaring ahead of the talks, with the US deploying a second aircraft carrier to the Middle East. The US military is preparing for the possibility of a sustained military campaign if the talks do not succeed, US officials have told Reuters.

Asked about the prospects for a deal, Trump said Iran sought tough negotiations but learned the consequences of such a hardened stance last summer when the US bombed Iranian nuclear sites.

Trump suggested Iranians were motivated this time to negotiate.

“I don’t think they want the consequences of not making a deal,” Trump said.

Prior to the US joining Israel in striking Iranian nuclear sites in June, Iran-US nuclear talks had stalled over Washington’s demand that Tehran forgo enrichment on its soil, which the US views as a pathway to an Iranian nuclear weapon.

Iran’s civil defence organisation on Monday held a chemical defence drill in the Pars Special Economic Energy Zone to strengthen preparedness for potential chemical incidents in the energy hub located in southern Iran.