Egypt's police have been implicated in an "unprecedented spike" in enforced disappearances since early 2015 aimed at quashing dissent, Amnesty International said in a report yesterday. "Enforced disappearance has become a key instrument of state policy in Egypt. Anyone who dares to speak out is at risk," said Philip Luther, Amnesty's Middle East and North Africa director.

The London-based human rights group said abuses had surged since the military overthrew the country's first democratically elected president, Mohamed Morsi, in 2013 and unleashed a crackdown on his supporters. Children were among those being kept at undisclosed locations for up to several months at a time "to intimidate opponents and wipe out peaceful dissent," the report said. The report documents 17 cases, including five children, who had disappeared for periods of "between several days to seven months," according to the statement.

One of them, Mazen Mohamed Abdallah, who was 14 in September, had been subjected to "horrendous abuse" including "being repeatedly raped with a wooden stick in order to extract a false 'confession'," Amnesty said.

Another child of the same age when arrested in January, Aser Mohamed, "was beaten, given electric shocks all over his body and suspended from his limbs in order to extract a false 'confession'," the rights watchdog said.

Egyptian authorities have denied they practice torture, but say there have been isolated incidents of abuse and those responsible have been prosecuted.

The National Council for Human Rights, the country's official rights watchdog, said on July 3 it had raised 266 cases of enforced disappearances with the interior ministry between April 2015 and the end of March. Many of them have since been accounted for.

Amnesty's report "exposes ... the collusion between national security forces and judicial authorities," said Luther. He accused them of being "prepared to lie to cover their tracks" or failing to investigate torture allegations, "making them complicit in serious human rights violations."

An average of three to four people disappeared each day, Amnesty said, citing Egyptian non-governmental organizations.

It said they were usually detained at their homes by heavily armed forces, adding investigations were rarely opened when family members complain.

Even then, authorities closed the investigations once they acknowledged the people were in the custody of the National Security Agency, the secret police apparatus.

Prosecutors "cruelly betrayed their duty under Egyptian law to protect people from enforced disappearances, arbitrary arrest, torture and other ill-treatment," said Luther. Counter-terrorism was "being used as an excuse to abduct, interrogate and torture people who challenge the authorities," he was quoted as saying in the report. An affiliate of DAESH has waged an insurgency in Egypt's northern Sinai region since Morsi's overthrow that has killed hundreds of policemen and soldiers.

The country was rocked by violence for weeks after Morsi's supporters set up protest camps and demonstrated against his overthrow. The police killed hundreds of his supporters in clashes, including more than 600 on Aug. 14, 2013, as they dispersed a Cairo protest camp.

Morsi, a senior Muslim Brotherhood leader, had won the country's first free election in 2012, more than a year after a popular uprising ousted veteran strongman Hosni Mubarak.

Rights groups have criticized Egypt for the mass trials and many death penalties handed down en masse.

The brotherhood was the largest political movement in Egypt and was delivering aid, social services and education facilities across the country with a moderate Islamist ideology, seeking to end poverty, foreign intervention, unemployment, social problems and corruption. The brotherhood was banned and declared a terrorist group after the military ousted Morsi in 2013.