A string of four bombings struck Cairo on Friday, including a car blast that ripped through the Egyptian capital's main security headquarters and wrecked a nearby museum of Islamic artifacts.
Six people were killed in the most significant attacks yet in Cairo at a time of mounting confrontation between the military-backed government and armed opposition groups. The bombings marked the symbolism-laden eve of the third anniversary of the 2011 uprising that toppled longtime ruler Hosni Mubarak.
The blasts shook and damaged nearby buildings, including a courthouse, and sent black smoke rising above the Egyptian capital as a large number of ambulances rushed to the scene.
One of the bombs targeted police vehicles near a metro station, Egyptian security officials told The Associated Press, and another exploded near a police center in Cairo's Alharam neighborhood.
Several floors of the high-rise security building were wrecked, with air-conditioning units dangling from broken windows, and the pavement outside was covered with piles of shattered glass, pieces of bricks and rocks. Shops and cars in the area were also damaged.
The Health Ministry said in a statement that at least 50 people were injured in the first attack.
No one immediately claimed responsibility for the blasts, but Egypt has seen a sharp rise in militant attacks targeting police and the military in the aftermath of the July 3 coup that ousted Islamist President Mohamed Morsi.
The office of interim President Adly Mansour vowed in a statement after the attacks that it is determined to "uproot terrorism" and said it could be forced to take "exceptional measures." It did not elaborate, but the turmoil raises the potential for the partial return of a curfew imposed on much of the country for several months after the crackdown on Morsi's supporters escalated in mid-August.
In a statement, the Muslim Brotherhood, which supports Morsi, condemned the attacks and suggested the security forces themselves were behind it to justify an even wider crackdown. It said the bombings were "a prelude to unjust, dangerous decisions."
The bombings came a day before the anniversary of the start of the 18-day mass uprising that toppled Mubarak. It also came hours after a celebration held by the country's military to honor Police Day.
The near-simultaneous blasts are the first in central Cairo since the surge of militant attacks that followed Morsi's ouster.
Al Jazeera and The Associated Press