A fabricated Kyodo News story announcing that Chinese warplanes had violated Japanese airspace over Okinawa was posted on a fake Yahoo News Web site, it was reported Wednesday.
Kyodo News and Yahoo Japan Corp., which have reported the incident to police, said they are considering taking legal action against the person who produced the fake article.
In the afternoon, a 30-year-old man in the city of Nagasaki telephoned Kyodo News' bureau there and said, "I did it, and I regret it."
He said he had wanted to attract public attention.
The police are investigating whether the man is indeed responsible for the fake report.
The site used a logo mimicking that of Internet portal Yahoo Japan's news site. The fake article said that the Pentagon had announced the "invasion" early Tuesday, and that the incident took place near China's gas exploration projects in the East China Sea.
The false report said the military action took place in connection with China's gas exploration projects in the East China Sea.
The fake article, dated Tuesday and ostensibly dispatched from "America," also said U.S. forces, the Self-Defense Forces and Chinese forces had exchanged fire in Okinawan airspace.
The Web site carried other news articles linked to stories on the genuine Yahoo Web site.
Yoshimasa Tanabe, deputy head of Kyodo News's general affairs bureau, said the story is totally groundless and that the Web site that published the story has nothing to do with his company.
"Such an act, which damages the credibility of Kyodo News is truly regrettable. We would like to investigate the case and take necessary measures," Tanabe said.
