Soldiers serving overseas are losing some of their online links.

A high-ranking Army official says the Defense Department will begin blocking access worldwide to YouTube, MySpace and 11 other popular Web sites on its computers and networks starting
Monday.

The memo sent Friday said such recreational traffic impacts the official Defense Department network and bandwidth ability, "while posing a significant operational security challenge."

Members of the military can still access the sites on their own computers and networks but Defense Department computers and networks are the only ones available to many troops serving in Iraq
and Afghanistan.