The Federal Trade Commission is to investigate Take Two Interactive, producers of Grand Theft Auto: San Andreas, following the discovery of pornographic scenes in the game. 

The FTC's Division of Advertising Practices is conducting an inquiry into advertising claims for the game.

Senator Hillary Clinton sent a letter to the FTC earlier this month calling for an investigation into how the code was included in the game.

She is also planning to introduce legislation to prohibit the sale of violent and sexually explicit video games to minors, and wants to put in place a $5,000 penalty for those who violate the law.

"The disturbing material in Grand Theft Auto and other games like it is stealing the innocence of our children and making the difficult job of being a parent even harder," said Senator Clinton.

"I am announcing these measures today because I believe that the ability of our children to access pornographic and outrageously violent material in video games rated for adults is spiralling out of control."

The troubles began for the games publisher when games modder Patrick Wildenborg created a piece of code called 'Hot Coffee' which unlocked a new section of the game.

This section involved a mission to seduce one of the game's female characters and features softcore pornographic images.

Take Two Interactive initially denied that the code was in the original game, but has since admitted that this is the case and has ceased manufacturing the game.

"The company intends fully to co-operate with the FTC inquiry, and believes that it acted in accordance with all applicable laws and regulations," said Take Two Interactive in a statement.

"The company co-operated with a recently concluded Entertainment Software Rating Board investigation into this matter, and has taken decisive and immediate corrective action."