An Al Arabiya reporter on the ground said that three policemen were killed at the scene. He also reported that a second gunman was involved in the attack, but managed to escape.
A picture of the alleged gunman's corpse published on the official Al-Ahram newspaper's website showed a bearded man wearing a bulky ammunition vest sprawled on a street.
The ISIS group's affiliate in Egypt has killed dozens of Christians in church bombings and shootings over the past year, and has threatened further attacks against the minority.
Egypt's Coptic Christians make up about 10 percent of the country's 93 million people, and are the largest religious minority in the region.
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