Egypt's army-backed authorities arrested the spokesman of the Muslim Brotherhood on Tuesday, the latest member of the Islamist organisation to be jailed since a July 3 coup, security sources said.

An arrest warrant had been issued for Gehad al-Haddad, who was active on social networks, as part of a crackdown that followed the military's overthrow of Islamist president Mohamed Morsi.

But Haddad had managed to escape arrest for weeks until police found him in a Cairo apartment along with other Islamist figures including the former governor of Qaliyubiya province Hossam Abu Bakr, the sources told AFP.

They were seized in the Nasr City neighbourhood, where Morsi supporters for weeks had held protests demanding his reinstatement and clashed with security forces.

Morsi and top figures of his Muslim Brotherhood movement, including supreme guide Mohamed Badie, are also in jail and facing trials.

Since Morsi's overthrow by the army on July 3 and his detention, more than 2,000 members of the Brotherhood have been arrested.

In mid-August the military-backed interim government launched a bloody crackdown on two pro-Morsi protest camps in Cairo, including in Nasr City, in which hundreds of people were killed.

Haddad's arrest come as an Egyptian court on Tuesday ordered the freezing of the assets of senior Brotherhood leaders, including Badie, his two deputies Khairat al-Shater and Rashad Bayoumi, as well as Salafist leader Hazem Abu Ismail and preacher Safwat Higazi.

The five are currently detained, accused of inciting the murder of protesters opposed to Morsi.

Around 15 Islamist politicians have already had their assets frozen as part of the crackdown that has fractured the organisational structure of the Brotherhood.

The new army-installed authorities have laid out a political roadmap which provides for parliamentary and presidential elections in 2014.

AFP