WASHINGTON - Facebook said Monday that it is blocking a website called "Web 2.0 Suicide Machine" that helps users delete their social network profiles.

The number one social network also said it had sent a "cease-and-desist" letter to another website, Seppukoo.com, which also helps you kill off your virtual identity.

The Web 2.0 Suicide Machine site, which features a hangman's noose on its homepage, deletes profiles, friends and other information on Facebook, MySpace, Twitter and LinkedIn for users who provide their account information.

"This machine lets you delete all your energy sucking social-networking profiles, kill your fake virtual friends, and completely do away with your Web2.0 alterego," it says.

Facebook, in a statement to AFP, said the suicide site was in violation of Facebook rules.

"Facebook provides the ability for people who no longer want to use the site to either deactivate their account or delete it completely," Facebook said.

"Web 2.0 Suicide Machine collects login credentials, which is a violation of our Statement of Rights and Responsibilities (SRR)," it said.

"We've blocked the site's access to Facebook as is our policy for sites that violate our SRR," Facebook said. "We're currently investigating and considering whether to take further action."

Facebook, which claims more than 300 million users, also said it had sent Seppukoo.com "a cease-and-desist letter for similarly violating our policies."

Seppukoo.com urges users to "impress your friends" and "disconnect yourself" by committing online suicide in the manner of Japanese samurai.

Ritual samurai suicide was known as "seppuku."

"As the seppuku restores the samurai's honour as a warrior, seppukoo.com deals with the liberation of the digital body," the site says.