Russia said talks aimed at salvaging an international agreement on Iran's nuclear programme got off to a "successful" start on Tuesday, with the US expected to join indirectly for the first time since President Joe Biden's arrival in the White House.
Biden has said he is ready to reverse the 2018 decision of his predecessor Donald Trump to withdraw from the landmark agreement, which was supposed to ensure that Iran never developed a military nuclear programme.
Mikhail Ulyanov, Russia's Vienna-based envoy to international organisations, said Tuesday's meeting between those parties still in the deal was "successful" though it would take time to restore the agreement.
"How long? Nobody knows. The most important thing after today’s meeting of the Joint Commission is that practical work towards achieving this goal has started," he tweeted.
Since the US withdrawal from the 2015 deal with Iran and re-imposition of sanctions on Tehran, remaining parties China, Britain, France, Germany and Russia have been struggling to save the agreement in the face of Iran's stepping up its nuclear activities.
Iran is demanding an end to the crippling sanctions imposed by Trump. It has refused to meet US negotiators at the latest talks, meaning European players will act as intermediaries.
Delegates from the current members of the pact met Tuesday at a luxury hotel in Vienna. Their discussions will continue on Wednesday, according to a diplomat familiar with the talks.
- 'Back on track' -
Two expert-level groups -- on sanctions lifting and nuclear issues -- have been tasked "to identify concrete measures to be taken by Washington and Tehran" to restore the deal, Ulyanov added.
The US delegation are due to meet in a different luxury hotel, also in downtown Vienna, with EU negotiators acting as go-betweens.
"We need to make the best of this diplomatic space to bring the JCPOA back on track," said a tweet from EU diplomat Enrique Mora, the chair of Tuesday's meeting, referring to the pact by its acronym.
"Our clear goal is to return to full and effective implementation of the agreement by all sides," Mora said.
Ahead of the talks, US special envoy Rob Malley suggested that the United States could be open to lifting sanctions and returning to the deal, comments Iran government spokesman Ali Rabiei called "promising".
"We find this position realistic and promising. It could be the start of correcting the bad process that had taken diplomacy to a dead end," he told reporters in Tehran on Tuesday.
Iran confirmed in January it was enriching uranium to 20 percent purity, well beyond the threshold set by the deal.
Rabiei reiterated Iran was ready to reverse the steps it had taken as soon as all sanctions imposed during the Trump administration are lifted.
"We do not accept a step by step approach," he said.
- 'Complex process' -
EU spokeswoman Nabila Massrali warned of a "complex process" ahead.
"We are at the beginnings of a complex process and it is premature to anticipate an outcome to this process... We do what is necessary to move forward," she told reporters at a press briefing in Brussels.
Massrali said "joint efforts must be made" to see "what sanctions can be lifted and how to settle the nuclear issue".
Kelsey Davenport, director for Non-proliferation Policy at the Arms Control Association think-tank, said the lack of direct Iran-US talks was not ideal but added that the EU was well situated to break the stalemate.
She called for a "bold first step by both sides" which she hoped would inject "much-needed momentum" into the process.
Washington, for example, could unfreeze Iranian funds held in foreign banks and facilitate humanitarian trade, and Tehran could stop enriching uranium beyond the levels agreed in the 2015 accord, said Davenport.
"The problem is all the irreversible things, like the research activities Tehran has undertaken," the diplomat pointed out.