In Egypt, Jihadists Release Video of an October Attack......

CAIRO — Egypt’s most lethal jihadist group has released a video that appears to show its militants carrying out an attack that killed more than 31 soldiers in the Sinai Peninsula last month, raising new questions about the readiness of the government’s troops to confront the insurgency.

The 30-minute video was the first to be released by the militant group, Ansar Beit al-Maqdis, since publicly declaring its affiliation on Monday with the Islamic State, the extremist group fighting in Iraq and Syria. In the video, which was released Friday on a Twitter account purporting to represent the group, Ansar Beit al-Maqdis promotes its status as a franchise of the Islamic State, calling itself “Sinai Province.”

The group had been widely suspected in the attack on Oct. 24 on the Karm al-Qawadis checkpoint, but the video represented its first formal claim of responsibility. The complexity of the assault, and the death toll, undermined the government’s repeated claims that it was prevailing against an insurgency that has killed hundreds of its soldiers and police officers.

The footage — which appears to show a government tank fleeing men with machine guns, and militants seizing a large cache of matériel that includes heavy weapons — provided further evidence of the military’s vulnerabilities. And it was a showcase for the brutality of their opponents, who can be seen carrying out drive-by shootings and executing wounded soldiers.

As depicted in the video, the attack unfolded in two stages, beginning with a suicide car bombing of the checkpoint. A man identified as the bomber gives a statement to the camera in Arabic, saying he is delivering a message to Egypt’s president, Abdel Fattah el-Sisi, from Sinai.

“We will be the swords that cut off your heads,” he says.

A red truck can be seen driving toward the base, followed by a huge explosion depicted from two angles. Black-clad militants in pickup trucks race toward the blast. Cameras — including one apparently mounted on a machine gun — capture dead soldiers on the ground, as the militants kill others.

An armored vehicle and a tank sit behind sand berms that offer little protection. Militants fire at another tank that races away.

Ansar Beit al-Maqdis rose to prominence last year after the military ouster of Egypt’s first elected president, Mohamed Morsi. In its statements, it has sought to justify its killings as retaliation for a violent crackdown by the security services.

The latest video repeated that theme: At one point, it cuts away from the carnage at the checkpoint to unrelated footage of soldiers torturing men that was widely shared in Egypt. Then the video returns to the checkpoint, where a half-naked man is seen kneeling, apparently pleading.

The video’s editors appeared to have taken pains to blur the area around the captured man’s underwear. But in a sign of the militants’ extremist sensibilities, as the men around him open fire, his face and his bloodied, bullet-riddled shoulders remain in view.