It comes after Iran warned on Monday it would not be rushed into a "quick" deal reviving its faltering 2015 nuclear accord with world powers, as negotiations in Vienna remain deadlocked.

Writing in the Financial Times, the EU's top diplomat Josep Borrell said: "This text represents the best possible deal that I, as facilitator of the negotiations, see as feasible.

"It is not a perfect agreement, but it addresses all essential elements and includes hard-won compromises by all sides".

Iran's chief nuclear negotiator Ali Bagheri wrote on Twitter on Tuesday: "The Coordinator has shared his ideas to conclude the negotiations. We, too, have our own ideas, both in substance and form, to conclude the negotiations which would be shared."

The 2015 deal gave Iran sanctions relief in exchange for curbs on its atomic programme to guarantee that it could not develop a nuclear weapon -- something it has always denied seeking.

But the United States' unilateral withdrawal from the accord in 2018 under then-president Donald Trump, and Washington's reimposition of biting economic sanctions, prompted Iran to begin rolling back on its own commitments.

Talks in Vienna that started in April 2021 to restore the deal -- known formally as the Joint Comprehensive Plan of Action, or JCPOA -- have stalled since March amid differences between Tehran and Washington.

The two sides negotiated indirectly through the European Union coordinator.

Borrell said the draft text "addresses, in precise detail, the sanctions lifting as well as the nuclear steps needed to restore the JCPOA."

He accepted it may not address all US concerns about Iran, and acknowledged there are serious reservations in Tehran about implementing a deal "after the negative experience of recent years".

But he said "decisions need to be taken now".

Borrell warned: "If the deal is rejected, we risk a dangerous nuclear crisis, set against the prospect of increased isolation for Iran and its people. It is our joint responsibility to conclude the deal."