Updated

Egypt's main terror group has claimed responsibility under the name of the Islamic State for an assault against the army last month which killed 31 in the northern Sinai Peninsula.

In a lengthy video message issued Friday on Islamic Jihadi forums, Egypt's Ansar Beit al-Maqdis 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."