The forthcoming phase of the Iran nuclear deal negotiations in Vienna, which may become the last one, may take several weeks, Russian Deputy Foreign Minister said on Wednesday.

Iran PressEurope: Sergei Ryabkov made the remarks at the Russia Investor Conference on Wednesday.

"We have almost arrived at the final stage. I feel reasonably optimistic. The process will certainly take not months, perhaps several weeks," Ryabkov said.

According to Sputnik, Russian Deputy FM added, "if all the necessary decisions are made and the final breakthrough happens in Vienna, it may be technically finalized within mere days." 

Head of Iran's negotiating team in the Vienna talks on JCPOA revival said after the sixth round of the talks that ended on Sunday that Iran wants guarantees from the current US administration that it would not follow in the footsteps of the former Trump administration in terms of leaving the deal again and re-imposing the sanctions.

Deputy Foreign Minister Abbas Araghchi said that "We need to achieve guarantees to make sure that what the former US administration did, in terms of re-imposing the sanctions and the JCPOA exit would not take place again."

With regard to extending a monitoring deal of Iran's nuclear activities that ends on June 24, Araghchi said that "Necessary decisions on Iran's stances and actions will be made in Tehran after the expiration of the technical agreement with the IAEA."

Meanwhile, the top Iranian negotiator said that he was not sure that the next round of Vienna talks would be the final round, stressing that "But if the other side can decide, it will be the final round."

He also pointed out the next round will be a "difficult round."

The United States, under former president Donald Trump, left the multilateral 2015 nuclear deal - officially known as the Joint Comprehensive Plan of Action (JCPOA) – signed between Iran and the P5+1 group of countries in May 2018 and restored the economic sanctions that the accord had lifted in addition to imposing new non-nuclear ones.

Tehran responded to the breach by taking a raft of remedial nuclear measures under the JCPOA’s Paragraph 36.

The Islamic Republic has insisted that it would go back on its steps once the US removed all the sanctions in one step and Iran verified them.