WASHINGTON (AP) — A Navy veteran detained in Iran for nearly two years has been released and started making his way home, with the first leg on a Swiss government aircraft, U.S. officials said Thursday. “The nightmare is over,” his mother said.

The U.S. special envoy for Iran, Brian Hook, flew to Zurich with a doctor to meet freed detainee Michael White and will accompany White to the United States aboard an American plane, the officials said.

White’s release was part of an agreement involving an Iranian-American doctor prosecuted by the Justice Department, and followed months of quiet negotiations over prisoners. The two countries are at bitter odds over U.S. penalties imposed after President Donald Trump withdrew the U.S. from the 2015 nuclear deal and over the killing by American forces of a top Iranian general in Iraq at the beginning of this year.

“I am blessed to announce that the nightmare is over, and my son is safely in American custody and on his way home,” White’s mother, Joanne White, said in a statement. She thanked the State Department and Bill Richardson, a former U.S. ambassador to the United Nations and onetime New Mexico governor, for raising her son’s case with the Iranians.

White, of Imperial Beach, California, was detained by Iranian authorities in July 2018 while visiting a woman he had met online and fallen in love with. He was convicted of insulting Iran’s supreme leader and posting private information online, and was sentenced to a decade in prison.

Despite widespread speculation, White’s release was not related to the deportation to Iran this week of Iranian scientist Sirios Asghari, the officials said. White's release was predicated on another prisoner deal, the details of which were to be released later Thursday.