Center for Strategic Communication

Just after 1 a.m. on Dec. 24, a massive explosion struck the Daqahliya security directorate in Mansoura, Nile Delta. Video and photos from Mansoura showed an explosion far larger than what was seen in Ismailia on Dec. 12. The exact cause of the explosion in Mansoura has yet to be determined, though early reports have suggested a car bomb.

The explosion, which killed at least 12 people and injured around 130, also caused a nearby bank building to collapse and destroyed a number of vehicles, state-run MENA reported. “Most of those killed were among policemen inside the security headquarters whose bodies were buried under the debris,” the Associated Press reported.

The number of wounded is the most in a single attack since the overthrow of the Muslim Brotherhood’s Mohammed Morsi in early July. Among the wounded are two top security officials, Reuters reported, citing state TV. MENA identified the two officials as Daqahliya security chief Major General Samy el-Mehy and Director of the Investigation Department Brigadier Said Emara.

The attack comes roughly a day after the Sinai-based jihadist group Ansar Jerusalem (Ansar Bayt al Maqdis) called on members of the security forces to repent and leave their positions. Ansar Jerusalem concluded its message by warning that those in the security forces who do not leave will have no one “to blame but himself.” “[W]e are the most resolute and determined to carry out the command of Allah and His Messenger to do jihad against you and fight you until all the religion is for Allah,” the group declared.

This is the not the first time that attacks have been reported in Mansoura since Morsi’s overthrow. On July 23, a bomb attack at a police station in Mansoura killed one person and wounded 19. More recently, on Oct. 28, three policemen were killed in a shooting attack on a checkpoint in the city.

Since the ouster of Mohammed Morsi on July 3, there have been more than 260 reported attacks in the Sinai Peninsula, most of which were carried out against Egyptian security forces and assets, according to data maintained by The Long War Journal.

Attacks by Sinai-based jihadists, Ansar Jerusalem specifically, have also taken place in the Egyptian mainland. On Sept. 5, the jihadist group carried out an assassination attempt in Nasr City on Egypt’s interior minister, Mohammed Ibrahim. A month later, an Ansar Jerusalem suicide bomber unleashed a blast at the South Sinai Security Directorate in el Tor, which killed three security personnel and injured more than 45. On Oct. 19, the Sinai-based jihadist group targeted a military intelligence building in the city of Ismailia. And on Nov. 19, the group claimed responsibility for the shooting attack on Lieutenant Colonel Mohammed Mabrouk, a senior national security officer, in Cairo. Ansar Jerusalem has repeatedly stated its intent to target police and military headquarters in Egypt.

The al Furqan Brigades, which are not believed to be based in the Sinai, have also claimed responsibility for a number of shootings and rocket attacks in the Egyptian mainland since Morsi’s overthrow. In contrast to Ansar Jerusalem, the group has yet to claim responsibility for any large car or suicide bombings.