In the past 48 hours, more than 1,000 Web sites have been hacked and defaced, according to F-Secure. The Internet security company suggests most of the vandalism was made in the response to the military action in the Gulf.

Among those attacked are a number of U.S. military sites, as well as commercial and political properties. Many were defaced with antiwar messages as the weight of protest mounts.

Perhaps most notably, the U.S. Navy Web site was hacked by an activist called Apocalypse. The message posted on the site read: "No War, U.S.A think they can tell the world what to do, It is not what you can do for your country, it's what your country can do for you! This defacement is dedicated to my bro."

Virus activity is expected to soar during the conflict and is starting to show signs of an increase.

Jack Clark, product manager at antivirus company McAfee, said: "Virus writers will use any occasion that they think will work on computer users, no matter how sick--be it the attack on the World Trade Center or the war with Iraq. They are just looking for attention and will use anything that will guarantee media attention."

This week, a new virus called Ganda, which takes advantage of people's interest in the war, was detected.

Clark believes there will be a lot more viruses launched in e-mails related to the war in Iraq. He said: "Virus writers will play upon people's curiosity for information about the war."

Silicon.com's Will Sturgeon reported from London.