CAIRO – Egypt’s judges Tuesday said that most of them would not oversee a nationwide referendum on a contentious draft constitution, as tens of thousands of opponents and supporters of the country’s Islamist president staged rival rallies in Cairo, four days ahead of the vote.

The demonstrations and judges’ boycott came hours after masked assailants set upon opposition protesters staging a sit-in at Tahrir Square, firing birdshot and swinging knives and sticks, according to security officials.

They later said that five “hardened criminals” were arrested in connection with the attack.