Two days after Muscat brokered a prisoner swap between Iran and Belgium, Sultan Haitham bin Tariq al-Said of Oman landed in Tehran on Sunday for a two-day visit that is anticipated to focus on regional diplomatic and security matters, according to Iranian state media.

Oman has historically served as a conduit between the West and Iran and facilitated the release of a number of dual nationals and foreign people.

On Friday, Oman helped secure the release of a Belgian aid worker, who was arrested in 2022 and sentenced to 40 years in prison and 74 lashes on charges including spying, in exchange for an Iranian diplomat sentenced to 20 years in prison in connection with a failed bomb plot in France.

But dozens of foreigners and dual nationals remain in jail in Iran, most facing espionage and security-related accusations. Rights groups have criticised the arrests as a tactic by Tehran to win concessions from the West by inventing charges, which Tehran denies.

Haitham is expected to meet Iranian President Ebrahim Raisi to discuss issues such as Tehran’s strained ties with Egypt and Iran’s disputed nuclear programme, Iranian state media reported.

The visit comes as Iran also faces renewed criticism of its human rights record and allegations that Russia is using Iranian drones in its war in Ukraine. Tehran denies supplying the drones for use in war.

Efforts by six world powers to revive Tehran’s 2015 nuclear deal have stalled since last September, amid growing Western fears about the clerical establishment’s rapidly advancing nuclear programme.

The deal, which Washington ditched in 2018 under then President Donald Trump, had imposed curbs on Iran’s nuclear activities that extended the time Tehran would need to produce enough fissile material for a nuclear bomb, if it chose to do so. Iran denies ever seeking nuclear weapons.