Iranian negotiator Seyyed Abbas Araqchi held three separate talks with representatives of Britain, France and Germany as well as European External Action Service (EEAS) Deputy Secretary-General Enrique Mora and envoys of Russia and China in the Austrian capital.
Mikhail Ulyanov, Russia's envoy to the UN atomic watchdog tweeted Friday that delegations provided their deliberations on sanctions lifting and nuclear issues through “informal consultations”.
On Thursday, senior negotiators, excluding the United States, initially met to set the tone in what diplomats anticipated would be a tougher round of talks to salvage the pact.
Two expert-level groups, seeking to marry lists of sanctions that the United States should lift with nuclear obligations Iran should meet, held discussions.
Iran refused to meet directly with US negotiator Rob Malley during the talks led by the European Union, whose envoys shuttled between the two sides in different hotels.
Ulyanov described Thursday talks "positive". "General impression is positive," he tweeted.
He also said heads of JCPOA delegations on Thursday met the head of the US delegation without Iran in an informal setting to discuss the ongoing work on restoration of the nuclear deal
"Currently I think the nuclear working group is more advanced, much more advanced, than (the) sanctions-lifting working group," Wang Qun, China's ambassador to the UN atomic watchdog, told reporters after the Joint Commission meeting of senior officials, Reuters wrote.
"So currently we should do away with all disruptive factors, moving forward as swiftly as we can on the work of negotiation, especially by zeroing in on sanctions-lifting."
Iran has repeatedly said that all sanctions must be rescinded first, warning that it may stop negotiations if the measures are not lifted. The administration of US President Joe Biden wants Iran to reverse measures it took beyond the limits of the deal in response to former president Donald Trump’s withdrawal.
"Iran’s “seriousness of purpose” in pursuing diplomacy was tested in the three years since Trump withdrew from the nuclear accord," Iranian Foreign Minister Mohammad Javad Zarif said on Twitter.
"Iran – by remaining in the deal – passed with flying colors. The Biden administration, however, has only shown a commitment to Trump’s maximum pressure."