Turtle Rock Studios and Valve have announced Left 4 Dead, an all-new IP to be released via Steam in 2007.

Left 4 Dead screenshot

Very little has been revealed about Left 4 Dead, but we know that it will be a co-op action game, and a glance at the only released image reveals a hoard of zombies surrounding a bunch of four armed characters.

There's not much else to say, but here's what co-founder and president of Valve, Gabe Newell, had to say about it.

"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 Newell. "What Counter-Strike did for multiplayer action games, Left 4 Dead will do for co-op games."

Left 4 Dead is currently expected for release in 2007, and expect a lot more info in the coming months.