Amnesty International said it has collected evidence that points at torture carried out at sit-ins by deposed president Mohamed Morsi’s supporters.

The international organisation said in a report released on Friday that "anti-Morsi protesters" have recounted how they were "captured, beaten, subjected to electric shocks or stabbed."

Mastour Mohamed Sayed, 21, told Amnesty that he and a group of 20 others were attacked by a group of Morsi supporters near the pro-Morsi sit-in at Rabaa Al-Adawiya in Cairo’s Nasr City district on 5 July.

According to the report, his attackers wore balaclavas and some were armed with knives or machine guns.

"We were eventually held under a podium [in the sit-in]…I was beaten with bars, and given electric shocks. I lost consciousness a few times," he said.

Sayed also told Amnesty he believed he heard a woman being sexually assaulted.

"My hands were tied behind my back, and I was blindfolded, but I could see a bit from underneath the blindfold… I could hear the girl screaming when she was given electric shocks. I could also hear a woman ordering her to take off her clothes. At that stage, I said that this was haram (forbidden), and was hit on the head. I then saw two bearded men go into the room and heard the girl screaming more…"

Sayed said his captors asked why he and other detainees supported General Abdel Fattah El-Sisi, who led the army’s move to remove Morsi amid mass nationwide protests on 3 July. Sayed was then reportedly allowed to leave the sit-in, but his identity card was not returned to him.

According to the report, eight bodies have arrived at the morgue in Cairo bearing signs of torture. Five of them were found near areas where pro-Morsi sit-ins were being held.

Egypt’s interior minister also stated cases of the alleged torture in a press conference last Saturday, saying nine were found dead and ten still receiving treatment.

"Six people were found dead in Al-Nahda Square [in Giza] and three others are in critical condition in the hospital, while three were killed in Rabaa Al-Adawiya [in Nasr City] and seven remain hospitalised," he said.

According to Amnesty’s report, witnesses near Al-Nahda sit-in reported seeing people murdered.

Hassan Sabry, 20, said that he was dragged by armed assailants into Oumran Garden, near Cairo University in Giza.

"They used plastic wires to handcuff me…They started to beat us with sticks all over the body. At least two of us were bleeding," he said.

Sabry then watched a bloodied protester have his throat slit and another being stabbed to death, according to the report.

The organisation called for an immediate investigation into the issue.

"Allegations that torture is being carried out by individuals are extremely serious and must be investigated as a matter of urgency," said Hassiba Hadj Sahraoui, Deputy Director for the Middle East and North Africa at Amnesty.