TOKYO (AFP) - A suspected explosive device damaged a bathroom at Tokyo's Yasukuni Shrine on Monday (Nov 23), but no one at the controversial war memorial was hurt, officials and news reports said.

Police received reports of a loud bang and smoke rising near the public bathroom inside the shrine on Monday morning, a spokesman said.

Public broadcaster NHK said the small blast occurred as a larger-than-usual number of people were visiting the shrine for an annual harvest festival.

Police found the ceiling and wall of the bathroom damaged and burned, NHK said, adding that they also found a battery and wire there.

A bomb unit attended the scene and police have now launched an investigation into whether the incident was a targeted attack.

"Fortunately, no one was injured," a shrine official said, adding that it had not received any threat in connection with the explosion.

The shrine honours millions of Japan's war dead, but also controversially includes several senior military and political figures convicted of war crimes.

Visits to the shrine by senior Japanese politicians routinely draw an angry reaction from Beijing and Seoul, which see it as a symbol of Tokyo's military past.