Iran’s envoy to the UN atomic agency will leave his post next month, in what may be a further sign of new President Hassan Rouhani’s desire for a fresh start with the outside world over its disputed nuclear programme.

Ali Asghar Soltanieh’s surprise departure comes after Rouhani last Friday appointed former Foreign Minister Ali Akbar Salehi, seen as a pragmatist, to head Iran’s atomic energy organisation, replacing a hardliner in the job.

Rouhani has pledged to improve Iran’s ties with world powers in an attempt to ease stringent international sanctions on the Islamic Republic over its nuclear programme, which it says is entirely peaceful but the West suspects has military aims.

Soltanieh, an energetic diplomat in his early 60s who often rails against the West in meetings of the Vienna-based International Atomic Energy Agency (IAEA), had been leading so far fruitless negotiations with the agency.

“I confirm that my mission, assignment, will be over on September 1,” nuclear physicist Soltanieh told Reuters on Wednesday. “I’m proud that I’ve served my country and I’m grateful for their trust and I will go back home of course to serve my country.”

It was not immediately clear whether his move was planned or was a more recent decision by Tehran.

One Western diplomat accredited to the IAEA said Soltanieh “was the face” in Vienna of the previous Iranian government and that his replacement may be another indication of Rouhani seeking a new atmosphere in Tehran’s international dealings.

There was also no word yet on who would replace Solta-nieh, who has held the job for seven years.