Negotiators at the Iran nuclear talks plan to announce today that they have reached a historic deal capping nearly a decade of diplomacy that would curb Iran’s atomic programme in return for sanctions relief, two diplomats said yesterday.

US Secretary of State John Kerry is signalling diplomats won’t conclude an Iran nuclear agreement by early on Friday morning, complicating American efforts to quickly implement any deal.

Nuclear talks between Iran and six world powers went past a deadline and into overtime as negotiators renewed efforts to hammer out an agreement.