In a lengthy video message posted on Islamic Jihadi forums, Egypt's Ansar Beit al-Maqdis or Champions of Jerusalem made its first claim of responsibility after pledging allegiance to the Islamic State leader Abu Bakr al-Baghdadi.
The video showed an elaborate attack in which a suicide car bomber rammed his vehicle into an army post, before trucks loaded with armed and masked men rained bullets and killed fleeing soldiers. The group vowed, "this is just the beginning" while describing Egypt's President Abdel-Fattah el-Sissi as "tyrant, and servant of the Jews."
Over the past year, the group intensified attacks against the Egyptian army and police after ouster of Islamist President Mohammed Morsi last year and subsequent crackdown on tens of thousands of his supporters. The group expanded its bombings and suicide attacks into Nile Delta cities and Cairo.
Last month's attack was the deadliest against the Egyptian army in decades. It prompted authorities to declare a state of emergency in much of the northern Sinai region. Authorities pushed through a longterm plan to create a buffer zone along its borders with Gaza Strip by evacuating residents living near the borderline and demolishing their houses.
In Friday's video message, the alleged suicide bomber, identified as Abu Hamza al-Ansari, appeared in military fatigues and a black turban and vowed "to the despicable el-Sissi, we will be the swords that will cut your throats, hands and legs."
After blowing up his car, the video showed footage for more than a dozen soldiers and others in civilian clothes with blooded faces after they were shot to death and piled up in a hole on the ground. A subtitle read that the soldiers were killed while trying to escape. Several were injured and moving before they were showered with bullets. One of the soldiers appeared alive in his underwear, was shot to death with several bullets.
The masked men then looted large amount of weapons and ammunition that were inside the tanks and armored vehicles abandoned by the slain soldiers. One man standing next to an army equipment, yelled, "good news to al-Baghdadi; victory is coming; we are your soldiers God willing."
Displaying what they called "spoils" of their assault, a man in black robe sat next to looted weapons and said, "what you are seeing now is only the beginning. You opened doors which you won't be able to close." He warned soldiers to abandon their camps else they will face similar destiny of those "in ranks of the tyrant."