Google Inc. and Yahoo! Inc. said the number of visitors to their Web sites surged after Michael Jackson's death this week, as people hunted for the latest news on the King of Pop.

Yahoo News attracted a record 16.4 million visitors, topping the 15.1 million on the day Barack Obama was elected U.S. president in November, the company said in a blog. On Yahoo's home page, the "Michael Jackson rushed to hospital" headline had the highest number of clicks of any story in the company's history. There were so many visitors to Google News that the service mistook search queries as an automated attack, the company said.

"As word spread of his death, millions and millions of people from all over the world began searching for information about the pop icon," R.J. Pittman, director of product management at Google, said in a blog posting. "Regardless of your story or personal opinions about this astounding performer, global interest in the King of Pop is undeniable."

Jackson was pronounced dead on June 25 in the emergency room at the UCLA hospital in West Los Angeles. The singer, who was preparing for a series of concerts in London starting next month, was believed to have suffered cardiac arrest, the hospital said.

Google, owner of the world's most popular search engine, said some visitors to Google News had to type in special codes to access stories because the site thought it was coming under attack from hackers. Searches for Michael Jackson on its search engine for mobile phones also jumped, the company said.

Twitter, Facebook

Other Web sites, including Twitter Inc. and Facebook Inc., were also buzzing with Michael Jackson news. Most of the top 10 topics on Twitter, the micro-blogging site, were devoted to Jackson.

The number of user updates on Facebook, the world's most popular social-networking site, more than tripled in the hour after the Jackson news began to break, according to Meredith Chin, company spokeswoman. The status update feature lets people post short messages of what they're thinking.