Thousands of supporters and opponents of Egypt's new Islamist president clashed in Cairo's Tahrir Square on Friday in the first such violence since Mohammed Morsi took office more than three months ago, as liberal and secular activists erupted with anger accusing the Muslim Brotherhood of trying to take over the country.

The two sides hurled stones and chunks of concrete and beat each other with sticks for several hours, leaving more than 100 injured, according to the state news agency.

Two buses used by the Brotherhood to bring in supporters were set aflame behind the Egyptian Museum, the repository of the country's pharaonic antiquities, and thick black smoke billowed into the sky in scenes reminiscent of last year's clashes. The melee erupted between two competing rallies in Tahrir. One was by liberal and secular activists to criticize Morsi's failure to achieve promises he had made for first 100 days in power, the other had been called by Morsi's Muslim Brotherhood—who wanted a rally to demand judicial independence following the acquittals of 25 Mubarak loyalists Wednesday.