The family of jailed Muslim Brotherhood leader Mohamed Al-Beltagy has cited abuses and violations against him in prison in Egypt.
Beltagy was detained in 2013, shortly after the military deposed Mohamed Morsi, Egypt's first democratically-elected president, in a military coup.
He was slapped with several jail terms on multiple charges, which he says were "politically-motivated".
In a Saturday statement, Beltagy's family said he had been placed in solitary confinement in a windowless cell for two months.
"In August, he was forced by two security officials to remove his clothes, tortured and pictured naked," the family alleged.
The family attributed the alleged abuses to Beltagy's accusations against President Abdel Fattah Al-Sisi of killing his daughter.
Beltagy's daughter, Asmaa, was killed when security forces violently cleared a pro-Morsi protest camp in eastern Cairo's Rabaa al-Adawiya in mid-2013.
Hundreds of protesters were killed and thousands injured in the dispersal.
Egyptian authorities could not be reached for comment on the accusations.
Egyptian authorities have launched a relentless crackdown on supporters of Morsi and his Brotherhood group, killing hundreds and detaining thousands.