Several Iranian financial, oil and other experts have returned to Vienna to rejoin discussions within the framework of nuclear negotiations with world powers.

The official government news agency IRNA reported on Saturday that in recent days representatives of the central bank, the oil ministry and deputy foreign minister for economic affairs have rejoined working groups discussing details of a possible agreement to revive the 2015 nuclear deal known as JCPOA.

Diplomats reported on Friday that three working groups had meetings in Vienna with experts from all participants in the agreement. One working group irons-out details and mechanisms related to lifting of United States’ sanctions and another group is discussing the process of Iran’s possible return to its obligations under the JCPOA.

The meetings that lasted six hours in total dealt with texts previously drafted and worked on outstanding issues, IRNA said.

Friday evening a one-hour meeting took place between Iran’s senior negotiators and China’s representative, as well as a two-hour meeting with the European Union representative Enrique Mora.

IRNA added that “serious discussions” took place on Friday in a “constructive” atmosphere.

The talks that started last April have not reached a political agreement to restore the JCPOA, with Iran returning to limits set by the agreement and the US lifting the most important sanctions imposed after former president Donald Trump withdrew from the deal in 2018.