TEHRAN, Iran (AP) — Tehran said late Tuesday that Oman thanked the Iranian government for “delivering” to Muscat a detained 85-year-old Iranian-American who had been cleared to leave the country for medical treatment.

Iran's Foreign Ministry said on its website that Oman's top diplomat called his Iranian counterpart to express appreciation for Tehran's decision to hand over Baquer Namazi, a retired U.N. children’s agency official, as a “humanitarian gesture." It remained unclear whether Namazi, who was detained in Tehran in 2016, had actually left Iran.

Oman has frequently served as a neutral mediator between Iran and the West.

Namazi was placed under house arrest for medical reasons in 2018 but prevented from leaving Iran despite his family’s pleas that he travel to receive emergency heart surgery after suffering multiple hospitalizations.

Last October, he underwent surgery in Iran to clear a blockage in an artery to the brain that his family and supporters described as life-threatening.

The U.N. announced this week that following heavy pressure on the Iranian government, Tehran had agreed to lift Namazi's travel ban so he could receive medical treatment abroad.

Namazi was arrested when he traveled to Tehran to visit his incarcerated son Siamak Namazi, a 49-year-old energy executive. Security forces had arrested the son, an advocate of closer ties between Iran and the West, months earlier while he visiting Iran on a business trip.

Both Namazis were sentenced to 10 years in prison in Iran on what the U.S. and U.N. say were trumped-up spying charges.