Blast targets bus in Cairo, 5 injured.

Five people were injured, one in a critical condition, when a bomb was hurled at a public bus in Egypt’s capital, Cairo, two days after 14 were killed in an attack on a police station in Nile Delta city of Mansoura.

The area hit by the explosion on Thursday in front of Azhar University in the busy district of Nasr City was cordoned and is currently being investigated, Ministry of Interior’s head of the explosives department General Alaa Abdel Thaher said, according to state-run newspaper Ahram Gate.

A second remote-detonation bomb was diffused around the same area, according to Abdel-Thaher, while state-run television reported that a third bomb was also diffused.

Investigations showed that the bombs were home-made and were planted in an advert placard in a road-divider, Major General Jamal Halawa, deputy director of Civil Protection in the capital, told Ahram Gate.

The bus passengers who sustained injuries were transferred to a nearby hospital, according to the newspaper report.

The blast comes a day after the military-backed government designated the Muslim Brotherhood a terrorist group and froze all of its activities and charity groups, raising the specters of more violence ahead of a nationwide referendum slated for mid-January on an amended constitution.

Black terrorism

Following Mansoura’s violence, the government vowed to fight “black terrorism,” a continuation of a war it has declared since the military-led ouster of Egypt’s first democratically elected President Mohamed Morsi in July.

Since the ouster, hundreds of Morsi supporters have been killed and thousands have been arrested, while suicide attacks targeting mostly police officers has killed more than a 100 in the eastern Sinai Peninsula.

A Sinai-based armed group known as Ansar Biet al-Makdis has claimed responsibility for al-Mansoura attacks that was denounced by the Brotherhood.

The Azhar University has witnessed months of almost-daily rallies by students denouncing the July ouster of Morsi, who hails from the Islamist group.