Al Qaeda confirmed Tuesday that it's No. 2 official — a former aide to Osama Bin Laden who rose to lead the terror group's powerful Yemen affiliate — was killed in a U.S. airstrike.

Rumors about Nasir al-Wuhayshi's death first circulated on social media and in the Yemeni press.

A video released by al Qaeda on Tuesday said Wuhayshi had been killed in a U.S. airstrike along with two other militants and that a successor, Qassim al Rimi, had been appointed.

Related: Meet the New Leader of al Qaeda's Most Dangerous Arm

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In the video, fellow commander Khalid Batarfi paid tribute to the slain jihadist, saying he had “participated with the first generation in fighting America” since the 1990s. Batarfi also threatened revenge on the U.S., saying al Qaeda would “target your economy … attack your interests and destroy them.”

NBC News partner Flashpoint Intelligence confirmed the authenticity of the video from the official media arm of the terror group's Yemen affiliate, al Qaeda in the Arabian Peninsula (AQAP).

In addition to leading AQAP — considered to be the terror organization's most important affiliate — Wuhayshi was said to be "operations manager" of al Qaeda Central, reporting directly to Ayman al-Zawahiri. Zawahiri assumed command of the terror group after bin Laden's 2011 death and retains leadership of al Qaeda in Pakistan, but his mobility is limited and he is unable to plan much of anything, said a U.S. counterterrorism official. On the other hand, said the official, Wuhayshi, "by virtue of where he is," can plan external operations against the West.

Wuhayshi, a 38-year-old Yemeni, served as a secretary to bin Laden at the time of the September 11 attacks and then rose in the al Qaeda hierarchy. After 9/11, he fled Afghanistan as U.S. forces moved in, and was arrested after crossing the border into Iran. Iranian authorities turned him over to authorities in his native Yemen, where he escaped from prison and reconnected with al Qaeda.

With the death of a succession of No. 2 candidates in 2011 and 2012, al-Wuhayshi rose to the second most important position in the terror group last year. The U.S. has posted a $10 million reward for his capture.

The airstrike that is believed to have killed al-Wuhayshi was one of two this weekend against leaders of the terror group's main affiliates.

On Sunday morning local time, U.S. aircraft bombed a location in Ajdabiya in eastern Libya while targeting Mokhtar Belmokhtar, the one-time leader of al Qaeda's north African affiliate believed to have been behind a deadly January 2013 attack on an Algerian natural gas plant. Libyan government officials have claimed Belmokhtar was killed, but there has been no U.S. confirmation of Belmokhtar's death.

AQIM social media, meanwhile, continues to claim that the strike in Libya did not kill Belmokhtar. One U.S. official said getting confirmation of Belmokhtar's death would be more difficult since the attack on his compound "was not a surgical strike." His location was flattened by multiple 500-pound bombs.