The daughter and son-in-law of Islamist cleric Youssef El-Qaradawi were arrested by Egyptian police and detained for 15 days on Sunday pending investigations on charges of planning terrorist attacks that target security forces.

Ola El-Qaradawi and her husband Hossam Khalaf, a leading member of the Islamist Wasat Party, are also being investigated for joining a banned group, a reference to the Muslim Brotherhood which was designated by Egypt as a terrorist group in 2013.

Cairo has been demanding that Qatar hand over Youssef El-Qaradawi, 90, who is considered the spiritual leader of the Brotherhood and is wanted in Egypt in connection with various criminal cases related to terrorism and inciting against the government.

Some members of the Wasat Party, which was formed by members who split from the Brotherhood in 1996, are in jail on terror-related charges.