Iran's foreign minister resigns suddenly, hours after Syrian President Bashar al-Assad's surprise visit to Tehran

Mr Zarif also frequently posts in English on Twitter — which is restricted within Iran — but has not posted any messages there for nearly a week.

It was unclear on Tuesday morning whether Mr Zarif was still officially in the role.

The semi-official Islamic Republic News Agency quoted Seyyed Abbas Mousavi, a spokesman at the foreign ministry, as saying he had resigned, but President Rouhani’s chief of staff “vehemently” denied reports it had been accepted.

There were reports Mr Zarif was unhappy with the Syrian leader’s unannounced visit to Tehran.

The Entekhab news agency said it had attempted to contact Mr Zarif and received the message: “After the photos of today's meetings, Javad Zarif no longer has any credibility in the world as the foreign minister!”

Mr Zarif was not present at any meetings between Bashar al-Assad and Hassan Rouhani. Syria has been a major recipient of Iranian humanitarian and military aid during its civil war.

Mr Zarif became Iran’s foreign minister in 2013 and is recognised in the West for his role as lead negotiator for a landmark nuclear deal with world powers in 2015.

Israeli Prime Minister Benjamin Netanyahu tweeted “good riddance” in response to the news.