The powerful attack that overwhelmed computers at U.S. and South Korean government agencies for days was even broader than initially realized, also targeting the White House, the Pentagon and the New York Stock Exchange.

Other targets of the attack included the National Security Agency, Homeland Security Department, State Department, the Nasdaq stock market and The Washington Post, according to an early analysis of the malicious software used in the attacks. Many of the organizations appeared to successfully blunt the sustained computer assaults.

The Associated Press obtained the target list from security experts analyzing the attacks. It was not immediately clear who might be responsible or what their motives were. South Korean intelligence officials believe the attacks were carried out by North Korea or pro-Pyongyang forces.

The attack was remarkably successful in limiting public access to victim Web sites, but internal e-mail systems are typically unaffected in such attacks. Some government Web sites — such as the Treasury Department, Federal Trade Commission and Secret Service — were still reporting problems days after the attack started during the July 4 holiday. South Korean Internet sites began experiencing problems Tuesday.