Enrique Mora, the European Union official chairing talks in Vienna on reviving Iran’s 2015 nuclear deal with world powers, said Wednesday that “substantial progress” had been made although there were “still things to be worked out.”

Mora said he would not “venture a date” but said he was “quite sure there will be a final agreement.” Mora had just chaired a meeting of the Joint Commission of the JCPOA (Joint Comprehensive Plan of Action) as the 2015 agreement is named.

The commission comprises remaining JCPOA signatories – China, France, Germany, Iran, Russia and the United Kingdom – who have been meeting for six weeks in Vienna with the indirect participation of the United States, which left the JCPOA in 2018 but is committed under President Joe Biden to re-joining.

Other participants delivered a similar message to Mora. Iran’s delegation leader, deputy foreign minister Abbas Araghchi said that while progress had been good, diplomats needed now to confer with their capitals before talks resumed next week.

Russian delegate and IAEA ambassador Mikhail Ulyanov, who Tuesday apparently provoked a 3.1 percent fall in oil prices after overly optimistic tweets envisaging an announcement Wednesday, tweeted that “significant” progress had brought agreement “within reach.”

German Foreign Minister Heiko Maas told reporters in Berlin that while “concrete results” made possible a result in “the next two weeks,” he could not predict results as “negotiations will be assessed again in the respective capitals.”

Maas described as “arduous” a process, undertaken by expert groups aside from the JCPOA Joint Commission, of identifying which US sanctions and which nuclear steps taken by Iran since 2019 beyond the JCPOA were needed to revive the agreement.

While the two-week window cited by Maas would close before Iran’s June 18 presidential election, which may complicate talks, a far nearer date of interest is Friday, May 21, when an interim arrangement expires for access of the International Atomic Energy Agency (IAEA) to Iran’s nuclear sites.

Current access takes place on terms agreed in February by IAEA chief Rafael Mariano Grossi after Tehran threatened to restrict access to the minimum required by the Nuclear Non-Proliferation Treaty.

Mora said Wednesday that Iranian representatives were meeting IAEA officials in Vienna over extending the current arrangements, under which the agency’s cameras are still rolling in the atomic sites although it has no immediate access to them. A statement from the ‘E3’ – France, Germany, and the UK – said it was vital to achieve continuity in IAEA monitoring in Iran.