|Police gather near the police headquarters, after a bomb blast occurred nearby, in Cairo, Egypt, Jan. 24, 2014. (Xinhua/Pan Chaoyue)
CAIRO, Jan. 24 (Xinhua) -- At least four people were killed in a powerful explosion which rocked a police headquarters in downtown Cairo early Friday, according to the online edition of Al Ahram newspaper.
The blast, which occurred at the Cairo Security Directorate in the Bab El-Khalk District, also injured 51 people, smashed windows of nearby buildings, stripped off parts of their facades and caused damage to several cars.
The newspaper quoted Interior Ministry spokesman Hani Abdel Latif as saying that initial investigations showed a car bomb might have been used in the attack.
Police arrived at the scene immediately after the blast and sealed off the scene. Ambulances were seen transporting the injured to hospitals.
About 500 hundred people are gathering at the scene, some chanting slogans against "terrorists," holding portraits of Abdel Fattah El- Sisi, the head of Egypt's armed forces, a Xinhua reporter said.
The blast also affected nearby Islamic Art Museum. Mohamed Ibrahim, the Minister of Antiquities, arrived at the scene to inspect the damage done to the museum.
After the blast, police and army forces deployed armored vehicles at major institutions and streets across the Egyptian capital, official news agency MENA reported, adding Nahda Square in the nearby governorate of Giza was completely sealed off.
Friday's attack came a day ahead of the third anniversary of the 2011 uprising against Hosni Mubarak, the former president who ruled Egypt for almost three decades. Police are to deploy across the capital in anticipation of protests by Islamists and youth movement members opposing the current military-backed government.
Since the deposition of Islamist president Mohamed Morsi by the military in early July, tensions are running high in Egypt with a string of bombings taking place across the nation, including a high-profile assassination attempt against the interior minister in September.
Islamist militants based in the restive northern Sinai Peninsula are blamed for most of the attacks, against whom the military had launched an massive crackdown operation.