A video apparently taken by the Japan Coast Guard of the Sept. 7 collisions between a Chinese trawler and patrol vessels off the Senkaku Islands has shown up on YouTube, prompting China to express "concern" over already strained bilateral relations.

The 44 minutes of footage, uploaded on the video-sharing website in six parts, shows the Chinese boat bumping into Japanese cutters twice while coast guard personnel can be heard repeatedly issuing warnings in Chinese and Japanese.

The government launched an investigation into how the video ended up on the Web.