SHANGHAI, Sept. 12 -- The headmaster of a Shanghai kindergarten has apologized after using Japanese military music in a children's musical performance.

The private Aurora Foreign Language Kindergarten played "The Warship March," a composition still used by Japanese maritime forces, to accompany pupils playing percussion instruments at a graduation show on June 27.

Footage of the show was uploaded onto the Internet by parents and triggered public condemnation, leading to an investigation by the education bureau of Shanghai Zhabei District.

The bureau said on Friday that it had urged the kindergarten to say sorry.

Headmaster Xia Miao apologized in a statement on Thursday, saying that a teacher downloaded the music without lyrics from the Internet, selecting the piece for its rhythm and without knowledge of the music's origin.

Nevertheless, the kindergarten's board of directors has suspended the teacher.

The education bureau urged teachers in schools and kindergartens to improve their political sense in organizing education activities.

There is great tension between China and Japan over maritime sovereignty disputes and the latter's perceived lack of remorse for its conduct in World War II, when it launched military aggression against China.