The remaining members of the floundering Iran nuclear deal are meeting in Vienna for the first time since Germany, France, and Britain initiated dispute procedures that could reimpose UN sanctions on Tehran.
The February 26 talks come as the signatories try to rescue the landmark 2015 accord, which has been faltering since U.S. President Donald Trump unilaterally withdrew from it in 2018 and enforced crippling sanctions on Iran.
The meeting, overseen by the European Union, is being attended by senior diplomats from Iran, Britain, France, Germany, China, and Russia.
They have promised to uphold the deal that saw Iran agree to reduce its program of developing nuclear weapons in exchange for an easing of sanctions, even without Washington's support.
However, since the U.S. withdrawal, Iran has stepped up its program in defiance of Washington's "maximum pressure" campaign.
"This is a chance -- though not of 100 percent -- to stop escalation before it's too late," Russian Foreign Minister Sergei Lavrov was cited as saying by the Russian Embassy in Vienna on Twitter.
Iran has since breached its main limitations, exceeding the stockpiles of heavy water and uranium allowed, the number and types of centrifuges it can operate to enrich uranium, and the purity of uranium.
As a result, in mid-January, the three European countries said they had "no choice" but to trigger a dispute mechanism in the accord, citing reduced compliance.
The process for ultimately reimposing UN sanctions consists of several steps, the final one of which is to notify the UN Security Council. The restrictive measures would then automatically be reinstated after 30 days unless the Security Council voted to keep them lifted.
Trump has called the deal 'fatally flawed,' in part because it did not restrict Tehran's ballistic-missile program or address its support for terrorist groups in the Middle East.
Iran insists its nuclear program is for civilian purposes only and that the Joint Comprehensive Plan of Action (JCPOA) allows the country to run reactors to generate power.
With reporting by dpa and AFP
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