Amnesty International has accused Nigerian security forces of routinely torturing and abusing men, women, and children as young as 12 years of age.

The human rights group said in a report on Thursday that security forces in the African country torture detainees in a violation of international law and Nigeria’s constitution.

“A wide range of torture methods are used by both military and police, including beatings; shootings; nail and teeth extractions; and rape and other sexual violence,” the rights group said.

According to the Amnesty, torture has become institutionalized in Nigeria and many police stations have an informal “officer in charge of torture.”

In its report, which was compiled over seven years, Amnesty said pervasive corruption, a practice of detaining people in order to collect bribes, and poor training contributed to the use of torture.

“Security officials are rarely held accountable for failures to follow due process or for perpetrating human rights violations such as torture,” the report further said.

Nigeria’s police force denied the accusations, saying the report consisted of “blatant falsehoods and innuendoes.”

They also criticized the Amnesty for not presenting its findings to Nigerian authorities first.