An eighth round of nuclear talks between Iran, the US, EU, France, UK, Germany, Russia and China began on Monday.
Alain Matton, spokesman for the EU, which is leading the talks, confirmed they had begun.
“The eighth round of the Vienna talks just started,” Mr Matton said on Twitter.
The new round of talks would be focused on the issues of guarantees and verification of lifting sanctions, Iran's Foreign Minister Hossein Amirabdollahian said at an event in Tehran on Monday.
“The most important thing for us is to reach a point where we can verify that Iranian oil will be sold easily and without any limits, that the money for this oil will be transferred in foreign currency to Iranian bank accounts and that we will be able to benefit from all the revenue,” he said.
Iran's focus remains the lifting of sanctions, being able to sell oil in an unrestricted manner, gaining access to frozen assets and being able to reap the economic benefits of the previous deal, he added.
Robert Malley, the US special envoy for Iran, will attend the talks in Vienna, a State Department official told The National.
“Special envoy Malley will lead an inter-agency delegation for the eighth round of talks in Vienna starting today,” the US official said.
The administration of US President Joe Biden is hoping for a “constructive resumption of talks, with all parties seeking to reach and implement a rapid mutual return to full compliance with the JCPOA”, she added, while casting doubt on Iran’s intentions and goals at the talks.
“It is too soon to tell whether Iran has returned with a more constructive approach.”
Although progress has been slow in Vienna, the previous round of talks ended with a degree of optimism. In a show of goodwill, Iran reached an agreement with the UN's nuclear watchdog, the International Atomic Energy Agency, to allow for its nuclear sites to be monitored and refitted with cameras.
Along with that, the parties in Vienna were able to agree on which points would be discussed at the next round of talks.
Before the last round of talks, there were concerns that neither Iran nor the US would be able to come to the table to work out a new deal, with Mr Malley saying a “period of escalating crisis” would occur should a deal not come to fruition.
Former US president Donald Trump withdrew from the deal and reimposed sanctions on Tehran.
Iran complied with the deal for a brief period after the US exit and then began ramping up its enrichment. Since then, Iran has enriched uranium to 60 per cent.
However, Iranian nuclear chief Mohammad Eslami told state TV on Sunday that the country “has no intention to produce nuclear fuel beyond the 60 per cent purity".
Before the Vienna talks, the EU said participants would “continue the discussions on the prospect of a possible return of the US” to the deal and examine how to best ensure the full and effective adherence to the agreement by all sides.
Mr Amirabdollahian, however, voiced his scepticism over the EU's role in the talks this week.
“We do not see the position of the European countries as constructive,” he said
He went on to reiterate Iran's main goal for the talks — the lifting of all sanctions.
The US has yet to agree to any sanctions relief, which is an issue that will be key to progress in Vienna.