SAN FRANCISCO — The video game industry on Wednesday changed to adults-only the rating of "Grand Theft Auto: San Andreas," a best-selling title in which explicit sexual content can be unlocked with an Internet download.

The decision followed intense pressure from politicians and media watch groups.

Rockstar Games, the producer of "Grand Theft Auto," said it is working on a new version of the game that would satisfy the original "M" for mature rating. It said it would provide new labels to any retailer willing to continue selling the version currently on store shelves.

Rockstar's parent, Take Two Interactive, also admitted for the first time Wednesday that the sex scenes had been built into the retail game — not just the PC version but also those written for Xbox and PlayStation2 consoles.

Company officials had previously suggested that a modification created by outsiders added the scenes to the game, last year's best seller in consoles.

"There is sex content in the disc," Take Two spokesman Jim Ankner told the Associated Press. "The editing and finalization of any game is a complicated task and it's not uncommon for unused and unfinished content to remain on the disc."

The sex scenes, inserted in a game whose main character seeks bloody vengeance on gang-filled streets while picking up scantily clad women, had prompted outrage from parent's groups and politicians, including Sen. Hillary Rodham Clinton, D-N.Y.

In a statement, the president of the Entertainment Software Rating Board (ESRB) said the sex scenes were programmed by Rockstar "to be inaccessible to the player."

But ESRB chief Patricia Vance also acknowledged that the "credibility and utility" of the industry-run board's initial "M" rating had been "seriously undermined."

Many retailers sell "M" rated games, which "may be suitable for persons ages 17 and older," according to the rating board, but won't sell "AO"-labeled games at all.

Take Two also said Wednesday that it expects to suffer financially. It lowered its expectations to set aside funds for returns of the games, and figured that net sales could decrease by more than $50 million during the quarter ending July 31.

The ratings change was vindication for Patrick Wildenbourg, the Dutch programmer who developed and freely distributed the modification that unlocked the controversial content in the game's PC version.

Such "mods" are wildly popular in the hard-core gaming community and — authorized or not — exploit the medium's interactive nature to extend the playing life of many popular titles.

Take Two president Paul Eibeler stressed in a statement that only an unauthorized "mod" makes the sex scenes available.

The Parents Television Council, another group that monitors sex and violence in the media, said it was pleased with the rating switch but called on Rockstar to voluntarily recall the game and offer refunds to anyone who purchased it.