Lawyers working on behalf of people seeking asylum in Japan filed a criminal accusation Monday against the head of the Higashi-Nihon Immigration Center and its guards, alleging they assaulted and injured detainees.

More than 50 detainees, mostly Myanmarese and Kurdish, at the center in Ushiku, Ibaraki Prefecture, went on a one-day hunger strike calling for better treatment earlier this month and some were injured when guards violently suppressed them, the lawyers said.

The accusation was filed with the Mito District Public Prosecutor's Office.