The State Department is working to secure the freedom of various Americans being detained in restive Yemen, officials confirmed Sunday. The announcement followed reports in the Washington Post that said "at least four" American citizens had been taken prisoner by the Houthi rebel group that has taken over much of the country. "We have seen reports that several U.S. citizens have recently been detained in Yemen. We are doing everything we can to get these individuals released," a State Department official told NBC News. "Due to privacy considerations, we do not have any further personal details or information to share."