The organization is calling for independent monitors to be given immediate access to detainees in all facilities in the wake of the coup attempt, which include police headquarters, sports centres and courthouses. More than 10,000 people have been detained since the failed coup.

Amnesty International has credible reports that Turkish police in Ankara and Istanbul are holding detainees in stress positions for up to 48 hours, denying them food, water and medical treatment, and verbally abusing and threatening them. In the worst cases some have been subjected to severe beatings and torture, including rape.

Reports of abuse including beatings and rape in detention are extremely alarming, especially given the scale of detentions that we have seen in the past week. The grim details that we have documented are just a snapshot of the abuses that might be happening in places of detention, said Amnesty Internationals Europe director John Dalhuisen.

"It is absolutely imperative that the Turkish authorities halt these abhorrent practices and allow international monitors to visit all these detainees in the places they are being held.

Detainees are being arbitrarily held, including in informal places of detention. They have been denied access to lawyers and family members and have not been properly informed of the charges against them, undermining their right to a fair trial.

On Saturday the Turkish government issued its first decree under new powers authorised by its declaration of a state of emergency. The decree dramatically increases the amount of time detainees can be held without being charged from four to 30 days. The change risks exposing detainees to further torture and other ill-treatment. The decree also provides for officials to observe or even record meetings between pre-trial detainees and lawyers, and detainees are restricted in who they can choose to represent them, further undermining the right to a fair trial.

Amnesty International spoke to lawyers, doctors and a person on duty in a detention facility about the conditions detainees were being held in.

The organization heard multiple reports of detainees being held in unofficial locations such as sports centres and a stable. Some detainees, including at least three judges, were held in the corridors of courthouses.

All of the interviewees wished to remain anonymous for security reasons. The organization heard extremely alarming accounts of torture and other ill-treatment of detainees, particularly at the Ankara Police Headquarters sports hall, Ankara Bakent sports hall and the riding club stables there.

According to these accounts, police held detainees in stress positions, denied them food, water and medical treatment, verbally abused and threatened them and subjected them to beatings and torture, including rape and sexual assault.