One of the four Americans being held by Shiite Houthi rebels in Yemen has been released following intervention by Omani authorities, the State Department confirmed. 

State Department spokeswoman Marie Harf said that freelance journalist Casey Coombs, who was injured, has been released and is in Oman. Coombs is a freelance reporter working for The Intercept online news site and other publications. 

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

A senior defense official earlier confirmed to Fox News that the Americans were being held. 

The department released a statement Sunday saying they were "doing everything we can to get these individuals released." The statement added that the department would not release personal information about those being held due to privacy concerns. 

The Washington Post, citing unnamed sources, first reported Sunday that the Americans were being held. The Americans are believed to be imprisoned in the Yemen capital of Sanaa, which Saudi Arabia has repeatedly bombed in a campaign to oust the Houthi rebels from power, the newspaper reported. 

Three of the four prisoners held private sector jobs and fourth holds dual American-Yemeni citizenship. None is a U.S. government employee, according to the Post. 

The Post report said those most recently detained are among dozens of Americans who were unable to leave Yemen or who chose to remain in the country after the U.S. closed its embassy. 

The Associated Press contributed to this report.