At least one person was killed when a primitive bomb exploded after being thrown at a police vehicle near a metro station in Giza, deputy Giza security chief Mahmoud Farouk told state TV.
TV footage showed a police cordon around El-Behous metro station in Giza's Dokki district.
At least 11 others were reportedly wounded in the attack.
Earlier on Friday, a major blast hit a Cairo police headquarters, killing at least four and injuring 51 others
.
Bomb attacks have become commonplace since the ouster of president Mohamed Morsi in July, but until Friday deadly attacks have largely taken place outside the capital.
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