An explosion at Cairo's police headquarters has killed at least five people and wounded dozens more, according to Egyptian authorities.
According to CNN, the blast rang through the city early Friday. It was followed by two smaller explosions near other police stations in other areas of the city, one of which left several injured.
USA Today calls the explosion, "The deadliest bomb blast in Egypt's capital since a military coup ousted Islamist president Mohamed Morsi last summer."
And NBC points out they came just a day before the third anniversary of the 2011 revolution that led to the downfall of Egypt's former authoritarian leader Hosni Mubarak.
Egypt's interior minister has promised to beef up security in areas where people are expected to gather to mark Saturday's anniversary with anti-government protests and rival celebrations.
The BBC reports the major explosion was caused by a car bomb, and that an al-Qaeda-inspired military group has claimed responsibility for the attack.
But other media outlets are reporting the explosions could have been caused by a suicide bomber, crude explosive devices or even a hand grenade. (Via The Guardian)
Egyptian officials say Saturday's activities could cause more violence in the city. A security message from the U.S. Embassy in Cairo warned American citizens to "limit their movements" over the weekend to ensure their safety.