The headquarters of Egypt's ruling Muslim Brotherhood - ransacked and burning on Monday.

The building was overrun by youths after those inside were evacuated, following a night of violence that killed at least eight people.

It was by far the bloodiest incident of Sunday's massive and mostly peaceful protests against the Brotherhood and President Mohamed Mursi.

A Brotherhood spokesman blamed the violence on thugs and said it would be demanding answers from police who failed to protect it.

But one of the witnesses of the night battle said those inside the headquarters has been heavily armed.

(SOUNDBITE)(Arabic) OPPOSITION PROTESTER SAMEH FATHY, SAYING:

"This is not an office, this is the Muslim Brotherhood Fortress. They are firing live ammunition and no one can even pass in front of the building, even when the ambulance tries to pass, they fire at it."

Several provincial headquarters of the Islamist movement have been attacked in recent days, in