Egyptian authorities have released a 12-year-old boy pending trial on Tuesday, three days after he was detained on charges of belonging to the Muslim Brotherhood, which the government outlawed in late 2013, according to the boy's lawyers and family.

"The boy was among eight people detained on Monday on charges of taking part in Brotherhood protests," Raouf Eissa, the boy's lawyer, told Anadolu Agency.

Mubarka Abdel-Khalek, the boy's mother, said her son had been arrested on Monday and had been held at a training camp for security forces in Egypt's northern Benha province.

She added that her son was released from a police station in the early hours of Thursday.

Egyptian officials were not immediately available to comment.

The Muslim Brotherhood was designated a "terrorist organization" by the Egyptian government in late 2013, following the ousting of Mohamed Morsi, Egypt's first democratically elected president and a Brotherhood leader.

The Brotherhood, for its part, says it is committed to purely peaceful activism.