SANAA — The leader of al Qaeda’s wing in Yemen has vowed to attack the United States, in a video apparently showing a gathering of the group celebrating a mass jailbreak of fighters.

In February, attackers mounted a bomb, grenade and gun assault on the main prison in Sanaa in which 29 inmates, including 19 jailed for terrorism-related crimes, escaped. 

The 15-minute video, dated March 2014 and posted on a website used by Islamists, shows masked men waving al Qaeda’s black flag and celebrating the arrival of the freed prisoners.

Its authenticity could not be independently verified.

“The Crusader enemy, dear brothers, still possesses cards which he moves around. We have to remember that we are always fighting the biggest enemy,” says a man speaking in the open in a mountainous area, whom the video identifies as its leader Nasser al-Wuhaishi.

“We have to remove the cross, (and) the bearer of the cross, America,” said Wuhaishi, who appeared with his face uncovered, wearing a T-shirt and sporting a dagger common among Yemeni men.

The video, titled “Images from the reception of the freed prisoners from Sanaa’s central prison,” included testimony from fighters involved in the jailbreak.

Abdulrazzaq al-Jamal, a journalist who has interviewed members of al Qaeda in the Arabian Peninsula (AQAP), said it was the largest known gathering of al Qaeda in Yemen.

“It included about 400 people, and these are not all the members of the group. This gathering is a confirmation that al Qaeda is gaining strength and influence,” he said.