Police have fired tear gas to disperse hundreds of Islamists rallying in Cairo and other cities against an upcoming constitutional referendum, the Associated Press reports.

Friday has traditionally been a day of protests for the supporters of Islamist President Mohammed Morsi since he was toppled in a July 3 popularly backed military coup. Islamist supporters of Morsi and his Muslim Brotherhood organization also now call for a boycott of the Jan 14-15 referendum.

One official, according the AP, said protesters in the eastern Cairo district of Nasr City hurled stones and empty bottles at security forces. He spoke on condition of anonymity as he was not allowed to brief journalists.

In the southern city of Minya, Maj. Gen. Osama Metwalli said protesters threw gasoline bombs at the police, who responded with tear gas.