Iran's lead negotiator in the Vienna talks, Ali Bagheri Kani, said that the Vienna Talks were moving forward with a positive trend.

He noted that Iran will limit its nuclear program in return for relief from the US, stressing that Tehran is serious about reaching a "fair agreement" in a short time if the US shows “goodwill” and “seriousness".

“The US must first lift sanctions, and Iran would verify the removal before returning to full compliance with the JCPOA”, he added.

Earlier, European negotiators stressed that talks to save the Iranian nuclear deal are "urgent".

The nuclear talks had restarted on November 29, following a five-month hiatus to revive the 2015 nuclear deal, which would see the US lifting the sanctions it imposed on Tehran.

"This negotiation is urgent... We are clear that we are nearing the point where Iran's escalation of its nuclear program will have completely hollowed out the JCPOA," negotiators from Britain, France, and Germany (E3) said in a statement.

"That means we have weeks, not months, to conclude a deal before the JCPOA's core non-proliferation benefits are lost," they added.

On good track

In the same context, Iran's Foreign Minister Hossein Amir-Abdollahian was quoted by IRNA on Tuesday as saying that the negotiations were "on a good track."

"With the goodwill and seriousness from the other parties, we can consider (reaching) a quick agreement in the near future," he said.

For his part, Moscow's Ambassador to the UN in Vienna, Mikhail Ulyanov, mentioned that the working group on nuclear issues held a "useful meeting" on Tuesday, whereas lifting sanctions was also discussed informally.

"We observe indisputable progress," he wrote on Twitter.

EU diplomat Enrique Mora, who is chairing the talks, said on Monday that all sides were showing "a clear will to work toward the successful end," stressing that "very difficult" negotiations lay ahead.