Officials from the UK, France and Germany are shuttling between two hotels in Vienna, serving as intermediaries between a US delegation and an Iranian delegation who are de facto in indirect negotiations on how to resurrect the 2015 nuclear deal. Diplomats from two other parties, Russia and China, are also the series of meetings.

Former US president Donald Trump abandoned the accord in May 2018. His successor, Joe Biden, has said he wants to restore US participation in the deal, otherwise known as the JCPOA, but wants Iran to return to verified full compliance with the agreement as a first move. Iran says it is prepared to restore such compliance—but only after the US drops all sanctions on Tehran. Overcoming that impasse is the task facing diplomats from the seven countries present in the Austrian capital.

Iran is sticking to its standpoint that face to face negotiations with the US cannot happen until the sanctions are gone.

Russia's ambassador to international organisations in Vienna, Mikhail Ulyanov, said on April 6 that brief preparatory talks were “successful”. Two expert-level groups on sanctions-lifting and nuclear issues have been set the goal of identifying specific measures to progress talks. Ulyanov cautioned that the restoration of the deal would not happen quickly, adding: "It will take some time. How long? Nobody knows. The most important thing... is that practical work towards achieving this goal has started."

US State Department spokesman Ned Price said prior to the initial talks: "We don't anticipate an early or immediate breakthrough, as these discussions, we fully expect, will be difficult."

US special envoy for Iran, Robert Malley, said last week he was exploring whether an agreement could produce a “road map” back to nuclear deal compliance for both sides.

The US knew it was "going to have to lift those sanctions that are inconsistent with the [nuclear] deal that was reached with Iran [in 2015]", he said.

The JCPOA is designed to ensure Iran cannot take a path to the production of a nuclear bomb. In return, it is supposed to protect the Iranian economy from major sanctions.

Trump pulled the US out of the deal, arguing it was not tight enough and should also cover other threats to Middle East peace such as Iran’s ballistic missile development programme and arming of militia groups in conflict zones. Iran has argued that Trump had no right to unilaterally abandon and demand renegotiation of a multilateral agreement that the US signed up to in good faith after years of painstaking negotiations.

The longer the US has remained out of the JCPOA, the more Iran has breached it.

On April 6, ISNA reported that Iranian scientists have tested improved IR-9 uranium enrichment centrifuges. The testing was announced by Behrouz Kamalvandi, a representative of the Atomic Energy Organization of Iran (AEOI).