Japanese video streaming website niconico has shut down the official channel of the anti-Korean activist group Zaitokukai, citing violations of the terms of service.

Dwango Co., which runs the site, said that content on the group’s channel fell under a category of material banned by the terms of service, which prohibit acts against public order and morals, but refrained from saying exactly what provision was violated.

Zaitokukai said on its website Tuesday: “We were notified by Dwango today of ‘the closure of the channel’ on the grounds of ‘violations of terms’ and our official channel page has been removed” with no specific explanation given. The group said it is looking into the situation and will keep its channel viewers posted.

The group has been engaged in hate speech against Korean residents in Japan. In December, the Supreme Court dismissed an appeal by Zaitokukai against a lower court decision to order the group to pay some ¥12 million ($99,400) in compensation to a Korean school in the city of Kyoto. The lower court also banned the group from demonstrating near the school.