July 8 (Bloomberg) -- The State Department’s Web site was among several U.S. government sites attacked by computer hackers, State Department spokesman Ian Kelly said today.

“The attack against our state.gov Web site started on July 5,” Kelly told reporters at his daily briefing. “It’s still ongoing, but I’m told it’s much reduced right now.” He said he hadn’t noticed “any real difficulties” in accessing the site.

Kelly declined to speculate on who was responsible for the attacks. “We’re investigating, but we can’t confirm the source of attacks yet,” he said.

The Department of Homeland Security is aware of the attacks and is advising agencies and private companies on “steps to take to mitigate against such attacks,” spokeswoman Amy Kudwa said in an e-mail earlier today.

The Associated Press reported that South Korea’s National Intelligence Service told a group of the country’s lawmakers today that it believes that North Korea or North Korean sympathizers in South Korea were behind attacks that limited access to South Korean Internet sites. The AP cited an unnamed aide to one of the lawmakers briefed on the information; the South Korean spy agency said it couldn’t immediately confirm the report.

To contact the reporter on this story: Juliann Neher in New York at jneher@bloomberg.net

Last Updated: July 8, 2009 13:33 EDT