More than a dozen people were killed and another 200 were wounded this week. Violence last weekend erupted when demonstrators rallied in support of a Salafist candidate barred from competing in upcoming elections.
Protesters in Cairo said Wednesday the violence was sparked by mobs aligned with the military-led government.
Amnesty International accused Egyptian army and security officials of doing little to intervene. Philip Luther, director of Middle East and North African programs at Amnesty, said that by the time security forces arrived near the building housing the Defense Ministry, it was too late.
"There appears to be no will within Egypt's ruling Supreme Council of the Armed Forces to prevent these tragic events," he said in a statement. "After the weekend attack, the authorities should have been prepared for the violence."
Medical sources told the rights organization that some of those killed in the political violence were shot and one died after his throat was cut. Amnesty International said it was unclear who was responsible for attacking protestors, however.
Some presidential candidates briefly suspended their campaigns in protest of the violence. Elections are scheduled for May 23-24.
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