An American believed to have committed suicide was found hanged in his police cell in the Suez Canal city of Ismailia on Sunday, Egyptian security officials said.

Security officials say the body of James Henry, 55, was found at noon in the Ismailia Awal police station.

Henry was arrested on 28 August on North Sinai's Al-Arish Road for reportedly breaking the curfew and was subsequently referred to military prosecution.

The curfew, at that time from 9pm to 6am, is part of the state of emergency imposed on 14 August following the violent dispersal of two sit-ins in support of ousted president Mohamed Morsi, which left hundreds dead.

Henry, who told authorities he was a retired officer, was living in an apartment in North Sinai's Sheikh Zuwayed prior to his arrest. He was reportedly on his way to Gaza, on the Egyptian border, when he was arrested.

At least nine foreign nationals were detained in Cairo on charges of inciting violence following the 14 August sit-in dispersal.

Last week, Egypt released two Canadians who had been in detention for 50 days without charge. They were arrested on 16 August after observing a pro-Morsi demonstration during which the Canadians say they saw at least 50 protesters killed.