Iranian Foreign Minister Mohammad Javad Zarif has unexpectedly announced his resignation in an Instagram post.

“I am grateful for magnanimity of the dear and courageous people of Iran and the respectable authorities’ over the past 67 months,” read the post published on late Monday local time.

“I sincerely apologize for inability to continue [my] service and all the shortcomings and flaws during [my] tenure,” it added. “May you be happy and proud.”

Seyyed Abbas Mousavi, spokesman at Foreign Ministry, confirmed to IRNA that Zarif has resigned.

President Hassan Rouhani is yet to confirm Zarif’s resignation.

Chief of Staff of the Iranian president, Mahmoud Vaezi, “vehemently” denied reports that Rouhani has accepted the resignation.

اخبار منتشر شده مبنی بر پذیرش استعفای دکتر ظریف از سوی رئیس جمهوری قویا تکذیب می شود. — Mahmoud Vaezi (@Dr_Vaezi) February 25, 2019

The 59-year-old diplomat started serving as the Islamic Republic’s top foreign minister after Rouhani took office in 2013.

He was reinstated in the post when the chief executive won a second term.

The foreign minister’s discourse has notably featured rejection of Iranophobia and strong promotion of international interaction.

Zarif played an instrumental role in the negotiations leading to the conclusion of a nuclear deal between the Islamic Republic and world powers in 2015.

He famously took the stage alongside the European Union’s foreign policy chief Federica Mogherini to announce the agreement, officially known as the Joint Comprehensive Plan of Action (JCPOA), in Brussels in February that year.