WASHINGTON (Reuters) – A U.S. Navy veteran detained in Iran since 2018 was freed on Thursday and was on his way back home, his family and President Donald Trump said, while an Iranian American physician will be allowed to visit Iran, his lawyer said.

Iran’s move to free Michael White and the U.S. decision to let Majid Taheri visit Iran appeared a rare instance of U.S.-Iranian cooperation, and a White House spokesman said White’s release may lead to an opening in the bitter relationship.

Iran’s foreign minister confirmed both moves.

White had been released from an Iranian prison in mid-March on medical furlough but had been held in Iran under Swiss custody. Switzerland looks after U.S. interests with Tehran because the United States and Iran lack diplomatic relations.

“I am to happy announce that Navy Veteran, Michael White, who has been detained by Iran for 683 days, is on a Swiss plane that just left Iranian Airspace. We expect him to be home with his family in America very soon,” Trump wrote on Twitter.

Separately, Taheri’s lawyer said the Iranian-American physician will visit family in Iran and seek medical treatment before returning to the United States as part of a U.S.-Iranian agreement that included White’s release.

A person familiar with the matter, speaking on condition of anonymity, said White’s release followed several months of discussions with Iran.

U.S. Special envoy Brian Hook had flown to Zurich with a doctor to meet White, a U.S. official said. The State Department did not have comment on the issue, but Secretary of State Mike Pompeo is scheduled to give a news briefing later on Thursday during which he is expected to talk about White.

White’s release is a rare bright spot in an otherwise deeply frayed relationship between the United States and Iran, which has grown more hostile since Trump took office in 2017.

Asked whether White’s release could be an opening in terms of U.S.-Iranian relations, White House spokesman Hogan Gidley told Fox News Channel, “Hopefully so. The president has built incredible relationships with leaders across this globe.”

U.S.-Iranian relations have been bitter since the Islamic Revolution toppled the U.S.-backed Shah of Iran in 1979 and ushered in an era of theocratic rule. Tensions flared after Trump pulled out of the 2015 Iran nuclear deal in 2018 and reimposed U.S. sanctions that have crippled the country’s economy.

Ties worsened after a Jan. 3 U.S. drone strike in Iraq killed Qassem Soleimani, the head of Iran’s elite Quds Force.

Both the United States and Iran have called for the release of prisoners due to the novel coronavirus outbreak. Iran is one of the worst-hit countries in the Middle East, while the United States has reported the highest number of deaths and infections in the world from the virus.

“My son, Michael, has been held hostage in Iran by the IRGC and I have been living a nightmare,” his mother Joanne White said in a statement announcing his release. “I am blessed to announce that the nightmare is over,” she said. IRGC is the acronym for Iran’s powerful Islamic Revolutionary Guard Corps.

White’s release came two days after the United States deported Sirous Asgari, an Iranian professor imprisoned in the United States despite being acquitted on charges of stealing trade secrets. Iranian media reported his arrival on Wednesday.

Both the U.S. State Department and Iranian officials have repeatedly denied that Asgari was part of a swap with White or anyone else, and said his case was separate.

Last December, Washington and Tehran worked on a prisoner exchange in which Iran freed U.S. citizen Xiyue Wang, who had been held for three years on spying charges, and the United States freed Iranian Massoud Soleimani, who faced charges of violating U.S. sanctions on Iran.