Sunni Arab leaders on Wednesday demanded an international investigation into allegations of the torture and abuse of detainees in Iraq, in what may become a major test case of Iraqi leaders’ willingness to tackle persistent reports of human rights abuses at the hands of the country’s security forces.

The demands follow Tuesday’s pledge by Shia prime minister Ibrahim al-Jaafari to open an internal investigation into the discovery by US troops of 173 prisoners, many starved and physically abused, in an interior ministry facility in the south Baghdad district of Jadriya.