Iranian Foreign Minister Mohammad Javad Zarif has resigned via social media, according to multiple news reports.

“I am apologising you for all the shortcomings … in the past years during my time as foreign minister. … I thank the Iranian nation and officials,” he posted on his Instagram.

The reasons for the resignation are currently unknown.

Zarif negotiated the 2015 Iran nuclear deal on the Islamic Republic’s behalf.

Whether his resignation will be accepted by Iranian President Hassan Rouhani remains to be seen.