Apple Computer Inc.'s Japan unit is investigating whether its iPods carry a computer virus, following the discovery of viruses in some of its digital video and music players in other countries, an Apple official said Thursday.

Less than 1 percent of the Video iPods put on the market after Sept. 12 have the virus, which affects Microsoft Corp.'s Windows system, Apple Japan Inc. said. Fewer than 25 cases have been reported so far, it said.

"We are checking the effects in Japan," said the official in Apple's public relations department. "We deeply regret that we could not catch the problem before shipping the products."

Apple Computer of the United States said Wednesday some of its iPod players were infected with a virus during production at a contracted firm. It said the virus can be eliminated with antivirus software that can be downloaded from its Web site.