"Their exact whereabouts are unconfirmed, but they are reportedly being held incommunicado at the State Security Intelligence (SSI) headquarters at Lazoghly Square, where all four were reportedly subjected to torture or ill-treatment," a statement said.

State security detained Wael Tawfiq and journalist Ibrahim al-Sahari on April 13. Amnesty said it has received reports that both activists were tortured and beaten.

Amnesty also said Mahmud Hassan Hassan was detained at an anti-war demonstration in front of the Egyptian Journalists' Union in the center of Cairo on April 12, while Ramiz Gihad was detained at a nearby coffee shop on the same day.

The group said both were "severely beaten" by security officers and that Gihad was subjected to electric shocks according to reports it received from a previously detained activist.

Since the start of the US-led war on Iraq on March 20 hundreds of anti-war activists were arrested by state security, according to Amnesty, which said most were released, but a few remain in detention.

Amnesty urged people to send appeals to Egyptian authorities urging them "to reveal exactly where they are being held, and give them access to lawyers, relatives and any medical attention they may require."

During the US-led attack on Iraq, Egypt was scene to some of the most vociferous anti-war demonstrations in the Middle East with most being sanctioned by the government and confined to the interiors of mosques, universities or stadiums.

Egypt's emergency laws, in force almost continuously since 1967 in Egypt, ban public protests.

SPACE.WIRE