YouTube is fighting off calls for the removal of "terrorist" videos from its pages.
US Homeland Security and Governmental Affairs Committee chairman Joe Lieberman has attacked the video upload site in an open letter.
He claims that the website shows assassinations, deaths of US soldiers and civilians, weapons training, incendiary speeches by al-Qaeda leadership, and other material intended to encourage violence against the West.
"Islamist terrorist organisations use YouTube to disseminate their propaganda, enlist followers, and provide weapons training", the senator writes to Google chairman and CEO Eric Schmidt.
"YouTube also, unwittingly, permits Islamist terrorist groups to maintain an active, pervasive, and amplified voice, despite military setbacks or successful operations by the law-enforcement and intelligence communities."
Lieberman is now urging Google to remove all content from YouTube with any connection to organisations including Al Qaeda.
YouTube has responded by pointing out it has removed some videos because they depict or advocate violence or contain hate content, but added that some videos that the Senator finds offensive will not be taken down.
"YouTube encourages free speech and defends everyone's right to express unpopular points of view. We believe that YouTube is a richer and more relevant platform for users precisely because it hosts a diverse range of views, and rather than stifle debate we allow our users to view all acceptable content and make up their own minds,"