Sweeping UN sanctions have been reimposed on Iran following failed last-minute nuclear talks, with France, the UK and Germany warning Tehran against "escalatory actions."

"The reimposition of UN sanctions is not the end of diplomacy," the foreign ministers of the three European nations, known as the E3, said in a joint statement on Sunday.

"We urge Iran to refrain from any escalatory action and to return to compliance with its legally binding safeguards obligations," they said.

The return of sanctions on Iran was triggered by the three countries at the UN Security Council (Germany through other two) over accusations that the country had violated a 2015 deal that aimed to stop it from developing a nuclear bomb.

Iran denies seeking nuclear weapons.