Police arrested four members of a rightwing group Thursday on suspicion of defaming the chief priest of Meiji Shrine last autumn by claiming in loudspeaker truck protests that he had embezzled money.

Toshio Takahashi, 60, head of Kokubo Doshisha (Group to Defend the Country), and group members Kei Sasaki, 69, Shin Sasaki, 34, and Osamu Nakagawa, 33, were arrested on suspicion of slandering the shrine's chief priest, Katsushi Toyama, 73, police said.

Investigators believe the acts were connected to Meiji Shrine's erroneous failure to use on invitation cards the appropriate honorific language to describe a visit by Emperor Akihito and Empress Michiko last April.

The shrine, dedicated to Emperor Meiji (1852-1912), used the phrase "ryo denka" ("their highnesses") instead of "ryo heika" ("their majesties").

The shrine's mistake drew criticism from various nationalist groups. A senior member of another group was arrested in February for allegedly breaking windows at Toyama's home in Setagaya Ward.

According to police, Takahashi and the other three paraded in loudspeaker trucks in the shrine's vicinity last September and October.

Their speeches featured slanderous claims, including that the chief priest had pocketed income from Meiji Jingu Stadium, investigators said. Between last September and February, the group paraded near the shrine in loudspeaker trucks some 150 times, according to police.