The Fox TV network has officially ordered a full season of its moderately successful U.S. action series "Terminator: The Sarah Connor Chronicles," sources say.

The unidentified sources said while the early portion of the series' second season hasn't been wildly popular, the TV network has requested nine more episodes of the science-fiction show, The Hollywood Reporter said Saturday.

The most recent episode of the Monday night series from Warner Bros. drew an estimated 5.7 million viewers, tying it with the NBC series "Chuck" among adults ages 18-49.

The Reporter said the full season order for the series, which is based on the successfully "Terminator" movie trilogy, comes after another sci-fi full-season order. Fox's first-season series "Fringe" earned a full season order.

The network also is preparing to enjoy predicted success with the forthcoming new season of "American Idol," the publication said.