Egyptian activists who spearheaded the revolt that toppled president Hosni Mubarak have called for mass demonstrations Tuesday to protest against verdicts handed down in the ex-strongman's murder trial. Mubarak and his interior minister Habib El-Adly were sentenced to life in prison Saturday, but six security commanders were acquitted over the killings of demonstrators during last year's uprising that left around 850 people dead. The ruling sparked nationwide outrage, with protesters taking to the streets in fury that no one had been found directly guilty of killing the protesters. The pro-democracy April 6 movement, the Coalition of Revolution Youth and the Maspero Youth Union among others called for a mass protest at the capital's iconic Tahrir Square at 1500 GMT Tuesday. The runners-up in last month's presidential election first round, leftist politician Hamdeen Sabbahi and moderate Islamist Abdel Moneim Abul Fotouh, will lead separate marches to the central square, they said in statements. They came third and fourth respectively in the May 23-24 election that has narrowed to a run-off later this month between Mubarak-era premier Ahmed Shafiq and the Muslim Brotherhood's Mohammed Mursi. Pro-democracy movements have capitalized on Egyptian national anger, calling for a return to Tahrir to press for the goals of the revolution. On Sunday, the state prosecutor said he would appeal against the sentences, but a judicial source said that the process could take weeks. Mubarak's defense team has also said it would challenge the ruling and said it was confident of winning on appeal. Five of the six acquitted security chiefs were freed early Monday. But the head of the now-dissolved state security apparatus, Hassan Abdel Rahman, remains in custody pending investigation into another case in which he is accused of destroying state security documents. Along with the acquitted police chiefs, Mubarak's sons Alaa and Gamal had corruption charges against them dropped on a technicality, sparking protests in Cairo, Alexandria and other cities.