DAKAR, Senegal (AP) — Human Rights Watch says armed groups causing unrest for more than four years in Central African Republic have been using rape and sexual slavery as a weapon of war — as revenge for people seen to be supporting the other side — with some of the attacks ordered or committed by commanders.

In a report released Thursday, the international rights group said that more than 300 documented cases of rape and sexual slavery have been carried out in Central African Republic by members of armed groups between early 2013 and mid-2017. The stigma of rape has meant there the problem is under-reported.

Human Rights Watch said such violence may constitute crimes against humanity, calling for action by and sustained support for the newly established Special Criminal Court.