Credit: Rockstar Games.

A parents group is warning about explicit footage in a new Grand Theft Auto video game, even as a California law banning such material from being sold to children was struck down as unconstitutional.

Common Sense Media, a nonprofit group that reviews games, movies and other entertainment for children, sent out a message late Thursday warning against Grand Theft Auto IV: The Lost and Damned.

"Heavy violence, strong language -- and now nudity," the group said. "Thought this M-rated game series couldn't go any lower? Think again." Common Sense Media reviewer Marc Saltzman said that The Lost & Damned, developed by Rockstar Games and published by Take-Two Interactive Software, contains depictions of full-frontal male nudity. It also includes graphically violent scenes, including one in which a gang member's face is pressed against the spinning wheel of a motorcycle -- splatter! The game, Saltzman said, "should be kept away -- far away -- from children."

The Lost and Damned is a $19.99 add-on game, released Tuesday, that's available only as a download on Microsoft's Xbox 360 game console. To play, one must already have Grand Theft Auto IV, which launched in April with little protest from parental groups. This version offers ...