The headquarters of the powerful Muslim Brotherhood in Cairo were stormed and ransacked on Monday following deadly clashes there between supporters and opponents of President Mohamed Morsi who hails from the Islamist group, according to an AFP correspondent.

The building in Cairo’s Moqattam district was set on fire before people stormed inside and began throwing things out of the windows. Some were seen leaving the building with fire bombs, helmets, flak jackets, furniture, televisions and documents.

Witnesses told AFP there were no Brotherhood members still inside the building, after they had been escorted out by an unidentified group of people earlier Monday.

Egypt is locked in a tense standoff on Monday after a day of huge rallies in which at least ten people were killed. The protesters demand the resignation of Islamist President Mohammed Morsi and some of them are saying that the military needs to step in, if Morsi refuses to step down.

The dead were all killed in Cairo or towns to its south. More than 600 were wounded during clashes between Morsi’s supporters and opponents, according to Al Arabiya reports.