Egyptian police have detained the daughter of a senior leader of the embattled Muslim Brotherhood group, according to a local activist.

Aisha Abd al-Bar, daughter of Brotherhood leader Abdel-Rahman al-Bar, was detained while visiting her jailed brother in the Nile Delta city of Mansoura, Mohamed Abu Hurayra, a spokesman for the Egyptian Coordination for Rights and Freedoms (ECRF), said in a Facebook post late Sunday.

The Egyptian authorities have yet to confirm Abu Hurayra's assertion.

Egyptian media outlets describe al-Bar as the "mufti" of the now-outlawed Muslim Brotherhood.

The Brotherhood has remained the target of a harsh government crackdown since mid-2013, when the army ousted Mohamed Morsi, Egypt's first freely elected president and a Brotherhood leader.

Aisha, a medical student, was expelled from Egypt's Al-Azhar University last year on claims that she was involved in "acts of violence".

It is not the first time for the child of a Brotherhood leader to be detained by the Egyptian authorities.

Last month, an Egyptian court jailed Anas al-Beltagi, son of Brotherhood leader Mohamed al-Beltagi, for five years for alleged illegal weapons possession. Al-Beltagi's other son, Khaled, has also been detained by Egyptian security forces.

Since Morsi's ouster, the Egyptian authorities have waged a relentless crackdown on dissent that has mainly targeted the ousted president's supporters and members of his Muslim Brotherhood group.

Over the course of the last two and a half years, security forces have killed hundreds -- and detained tens of thousands -- of Brotherhood members and Morsi supporters.

Last week, a Geneva-based NGO said as many as 4,000 Egyptian civilians had been detained and referred to military courts within the last year alone.