The mother of an American hostage released by Shiite Houthi rebels in Yemen says her son suffered a back injury and is still in shock, but that he's doing well considering the ordeal.

Freelance journalist Casey Coombs, 33, is stable in a hospital in Oman and is expected to return to Seattle in the coming days, said his mother, Jill Hammill. She found out Sunday that her son was freed after being taken by rebels on May 17.

She's shocked and overjoyed, Hammill said.

"It was a miracle," she said by phone from her home in Seattle. "We didn't know if we would see him again."

Coombs was one of several Americans being held by Shiite Houthi (HOO'-thee) rebels in Yemen. He has been freed following mediation by Omani authorities, State Department spokeswoman Marie Harf said.

The State Department is working to win the release of several Americans detained in Yemen, Harf said.

The Washington Post reported on Friday that the Houthis had cleared one of four American prisoners for release. It said three of the four held private-sector jobs, and the fourth holds dual U.S.-Yemeni citizenship.

In a brief telephone conversation with his mother after his release, Coombs said that he wasn't badly treated but that it was still a difficult experience, Hammill said. She said she hasn't heard the whole story but that he planned to reveal details of what happened when he returns to the U.S.

"He sounds extremely relieved," Hammill said. "He said he's still trying to process the whole thing. Sounds like he's still in shock."

Coombs is a freelance reporter who was working for The Intercept online news site and other publications. Emails to the Intercept seeking comment were not immediately returned.

His mother said he had been in Yemen for three years doing stories about humanitarian issues. He and his sister grew up in Utah, and Coombs has several degrees from the University of Utah: bachelor's degrees in English and anthropology and a master's in international affairs. The family recently moved to Seattle.

Coombs reported in the Intercept in early May that he was having trouble leaving Yemen. He was trying to get evacuated when he was taken by the rebels, Hammill said.

Despite being held hostage, she expects her son to continue being a freelance journalist.

"That's who he is. It's in his blood," Hammill said. "But he won't be doing it in Yemen."