CAIRO - A prominent Egyptian blogger convicted of insulting Islamist president Mohamed Morsi is facing fresh charges of inciting violence, judicial sources said on Tuesday, in a case that has triggered accusations of a crackdown on dissent.Ahmed Douma was sentenced to six months in jail on Monday for calling Morsi a criminal and a murderer in media interviews.He was initially allowed to pay 5,000 Egyptian pounds ($720) bail to leave prison pending an appeal, but the new charge meant he would now stay behind bars, state media reported.The case has enraged pro-democracy activists who have accused Morsi of using the same restrictive practices as his predecessor Hosni Mubarak, who was ousted in a popular revolt in 2011.Douma's supporters called for a demonstration on Wednesday in front of the High Court to call for his release."It is clear that there is an attack against Ahmed Douma, especially ... They want to send a message to all the youth of the revolution through him," his lawyer Ali Soliman said.