A source close to the family with direct knowledge of the case identified Darden, 45, as one of the captives. The source tells CNN that Darden was taken hostage in March of this year by Houthi rebels, and so far they have not asked for a ransom.

Darden was captured while working for the New-Orleans based company Transoceanic Development, according to the unnamed source. Darden was born and raised in Atlanta, Georgia, but has been living abroad for the last couple of years.

The family is working directly with the State Department and with Darden's company.

"We are aware of reports that several U.S. citizens are detained in Yemen. Due to privacy considerations, we do not have any further personal details or information to share. The protection of U.S. citizens overseas is one of the Department of State's highest priorities. We strive to assist U.S. citizens detained abroad whenever possible," the U.S. State Department said.

Transoceanic Development issues a statement Monday, saying, "We have been working tirelessly since March with governments and other organizations globally to secure the release of Scott Darden, who was in Yemen coordinating the warehousing and delivery of humanitarian aid as part of his job in international logistics. We continue to call on the Houthis to immediately release Scott so that he can be reunited with his family."