The U.S. Department of Defense plans to block employee access to 13 websites Monday, including YouTube and MySpace.
The department's computer systems are being used more often for personal surfing, decreasing Internet availability and presenting security risks.
"The Department of Defense has a growing concern regarding our unclassified Internet," a department release explained.
The department decided to implement the ban after noticing its resources were being tied up by employees using the sites for entertainment, such as listening to music or watching videos.
"This recreational traffic impacts our official network and bandwidth availability, while posing a significant operational security challenge."
The restriction bans almost 3 million employees, including those working overseas, from accessing the sites using the department's computers.
They're also urged to be cautious about information they transmit from their home computer to work.
"Exercise caution when forwarding any links or files from these sites to Department of Defense computers or networks, (as they could) create an opportunity for hacking and virus intrusion," the document explained.
The department said that sending personal videos, photos and data files can compromise sensitive unclassified information and increase risk of identity theft.
The U.S. military already barred its employees from sharing classified information while using the Internet and blogging, but this new restriction will prevent them from using the 13 sites altogether.
Other banned sites include mtv.com, photobucket.com, and stupidvideos.com.
