Zarif has been a key player in negotiations around Iran's nuclear programme.
Iranian president Hassan Rouhani has rejected the resignation of his foreign minister Mohammad Javad Zarif, according to the state-run IRNA news agency.
Zarif announced on Instagram on Monday night that he wanted to step down. He has been under pressure from hardliners in parliament over his handling of the fallout from Donald Trump's withdrawal from the 2015 nuclear deal.
Zarif is a key ally of Rouhani and has also enjoyed good relations with the European Union. An EU source told Euronews yesterday that the bloc's foreign policy supremo Federica Mogherini hoped that Zarif's resignation would be rejected.
Zarif posted again on Instagram this morning to thank the Iranian people and their officials for their support, saying that he had always been committed to serving his country.