LAGOS, Nigeria (AP) — Nigeria is illegally holding hundreds of people suspected of participation in violence by a radical Islamist sect in inhumane conditions and without access to lawyers, a rights group warned Thursday.

The report released by Amnesty International alleges most of those imprisoned around the country are held without criminal charges and suggests that some have been summarily executed by security forces before facing trial. Some of those detained told the rights group that they were shackled for days, forced to sit in their own excrement in overcrowded cells while watching other prisoners get beaten and coerced into confessions.