Indirect talks between the United States and Iran on bringing both sides fully back into adherence to the 2015 nuclear deal are making steady progress and will resume on Friday, the head of Russia’s delegation said on Saturday.

The talks started last month in Vienna with the remaining parties to the deal – Iran, China, Russia, Britain, France and Germany – meeting in the basement of a luxury hotel, and the United States based in another hotel across the street. Tehran has refused to hold direct meetings with U.S. officials.

The United States pulled out of the deal in 2018 under President Donald Trump and reimposed sanctions against Iran. Tehran responded as of 2019 by violating many of the deal’s limits on its nuclear activities.

“We should not expect breakthroughs in the coming days,” Russia’s ambassador to the U.N. nuclear watchdog, Mikhail Ulyanov, told reporters after a meeting of the remaining parties that wrapped up the third round of talks. He was the only official to address reporters.

“We need simply to continue diplomatic, day-to-day work, and we have all the reasons to expect that the outcome, (the) final outcome, will be successful and it will come quite soon, in a few weeks,” Ulyanov said, noting that talks will reconvene on Friday.

The break in talks was widely expected as diplomats said officials from many countries are also involved in the Group of Seven foreign ministers’ meeting in London that begins on Monday and ends on Wednesday.

Moscow is generally one of the more optimistic voices at the talks. On Friday, U.S. National Security Adviser Jake Sullivan said the talks were in “an unclear place”, meaning it was uncertain whether they would lead to an agreement.