News.com.au is reporting that a Japanese broadcaster has voiced anger and apologized after sponsoring a weekend concert at which a rock band played the Internet footage showing the beheading of a Japanese hostage in Iraq.
Tokyo Broadcasting System said it had no forewarning of the stunt.
"Showing this kind of video in public can never be forgiven on humanitarian grounds," the network said in a statement.
"As the sponsor, we offer deep apologies to the family of (Shosei) Koda, people who came to the concert and other people concerned," the statement said, without naming the band that showed the video.
Footage of Islamic militants decapitating the 24-year-old backpacker was shown on a large screen during Sunday's concert in Urayasu, the city east of Tokyo that hosts Tokyo Disneyland.
KLACK, a Japanese band that was one of 12 groups featured in the concert, showed the video for more than 10 minutes, local media reported.
Koda, described as a gentle but naive young man, became Japan's only hostage executed in Iraq after travelling to Baghdad as a tourist and searching aimlessly for a hotel.
An al-Qaeda linked group associated with Iraq's most wanted man, Abu Musab al-Zarqawi, posted a video on the Internet demanding that Japan withdraw its troops from Iraq within 48 hours.
The demand was rejected by Tokyo.
A week later, the group released footage of three hooded men pouncing on Koda and beheading him.