Law enforcement officials in the U.S. and South Korea were stepping up their efforts Wednesday to halt a rash of denial of service cyber attacks against more than 25 government agencies and companies. While the source of the attacks wasn't pinpointed as of Wednesday morning, officials said they suspected the attacks originated in North Korea or from groups sympathetic to North Korea.

In the U.S., some government agencies including the Treasury Department, the Transportation Department and the Federal Trade Commission were down for much of the July 4th holiday weekend. Some sites were said to still be affected, although US officials said they believed no data had been stolen.

"We see attacks on federal networks every day, and measures in place have minimized the impact to federal Web sites," Department of Homeland Security spokesperson Amy Kudwa told the Washington Post. The newspaper reported that it, too, had been a target of the attacks, although the Post's Web site was up and functioning well Wednesday. A spokesperson for the FTC said its cyber attack countermeasures performed well and the agency's web sites have been up and running most of the time.

According to the South Korean National Intelligence Service, the coordinated attack occurred when some 20,000 computers -- most of them in South Korea -- were taken over in the cyber attack. The computers had been infected with rogue software and were remotely ordered to repeatedly bombard the targeted sites.

If the attacks did indeed originate in North Korea, the government there would likely have been involved. The North Korean telecom service is generally available only to government employees. The communist country has relatively modern telecom facilities. For instance, Egypt's Orascom Telecom recently deployed a 3G wireless network in North Korea.

North Korea has embarked on a belligerent campaign in recent months, provoking neighboring countries and the international community with a stepped up missile campaign.

At last count, 11 US Web sites had been targeted. Even the White House was hit, although officials said there was no disruption of service on the site. Other federal agencies targeted included the Department of Homeland Security, the Defense Department, and the Federal Aviation Administration. Private sites that were affected included those operated by the New York Stock Exchange and the Nasdaq exchange.

Several South Korean government agencies as well as banks and newspapers were also hit by the attacks, although the South Korean intelligence agency said all sites were back to normal Wednesday morning.

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