Turtle Rock Studios and Valve Software have announced "Left 4 Dead," an upcoming co-op multiplayer game from the creators of Counter-Strike.

"By leveraging its industry-leading AI technology and years of Counter-Strike development experience, Turtle Rock is building upon the elements that make Counter-Strike successful and applying them to Left 4 Dead," said Gabe Newell, co-founder and president of Valve. "What Counter-Strike did for multiplayer action games, Left 4 Dead will do for co-op games."

"Left 4 Dead is built atop the most advanced version of the Source Engine and introduces version 2 of Turtle Rock's artificial intelligence (A.I.) technology.

Left 4 Dead will debut on the PC in 2007."

A game logo was released along with this announcement: