Iranian Foreign Minister Mohammad Javad Zarif, who was the lead negotiator in a landmark 2015 nuclear deal with major powers, has abruptly tendered his resignation, although there was no sign President Hassan Rouhani had accepted it.

Zarif offered an apology for his “shortcomings” in the unexpected message onInstagram on Monday, with prominent members of parliament immediately calling for Rouhani not to accept the resignation.

Zarif, 59, has served as Rouhani’s foreign minister since August 2013 and has been under constant pressure from hardliners who opposed his policy of detente with the West.

“I apologise for my inability to continue serving and for all the shortcomings during my term in office,” Zarif said in the message posted on his verified Instagram account.

He thanked Iranians and “respected officials” for their support “in the last 67 months”.

The resignation was confirmed by an informed source, however, in a tweet, Rouhani’s chief of staff strongly denied reports it had been accepted by the president.

Zarif gave no explanation for his resignation.

According to the semi-official ISNA news agency, Zarif was not present at any of Assad’s meetings with Iran’s supreme leader Ayatollah Ali Khamenei and Rouhani.

Entekhab said it tried to reach Zarif and received the following message: “After the photos of today’s meetings, Javad Zarif no longer has any credibility in the world as the foreign minister!”

In an interview with the conservative Jomhoori Eslami daily published on Tuesday, Zarif said: “everything will be lost, when there is no trust in the manager of foreign policy.” (AFP)