Al-Qaeda's second-in-command in the Arabian Peninsula, Said al-Shihri, and six others were killed in a missile strike in Yemen's Hadramawt province Monday, the U.S. and Yemeni officials said. The missile was fired from a U.S.-operated unmanned drone.

However, this is not the first time that the al-Qaeda's deputy leader, who was a former Guantánamo Bay detainee, was reported killed. Al-Shihri's death was rumored in December 2009 following an air raid in the eastern Shabwa province of Yemen.

If confirmed, al-Shihri's death "would be a deeply significant blow against AQAP (Al Qaeda in the Arabian Peninsula)," CNN terrorism analyst Paul Cruickshank said in a report. An unnamed Yemeni government official told the CNN that the officials were waiting for the DNA confirmation to ascertain al-Shihri's death.

According to an Associated Press report, two senior U.S. officials have confirmed al-Shihri's death but declined to confirm any U.S. involvement in the attack.

The Yemeni defense officials told the AP that a local forensics team, with U.S. expert assistance, had identified al-Shihri's body on the ground. Yemen's Defense Ministry issued a statement Monday saying al-Shihri and six companions were killed during an operation by the Yemeni armed forces in Wadi Hadramawt, without furnishing further details.

Al-Shihri has been the deputy leader of AQAP, an Al-Qaeda affiliate based in Yemen, since its inception in January 2009, according to U.N. Security Council data concerning the militant network.

Under Al-Shihri's command, AQAP was responsible for the March 2009 suicide bombings against South Korean tourists and government officials in Yemen that killed four and for the kidnapping of nine foreigners in Yemen - and the subsequent execution of three of them - in June 2009.

He is believed to have played a critical role in the August 2009 assassination attempt against Saudi Prince Muhammad bin Nayif, the Assistant Minister of Interior for Security Affairs. Al-Shihri is also believed to have played a key operational role in the September 2008 attack against the U.S. Embassy in Yemen and in the December 2009 failed bombing of a Northwest Airlines flight from Amsterdam to Detroit.

As deputy leader of AQAP, al-Shihri has been involved in identifying targets, recruiting new members, assisting with training and attack planning and tasking others in the preparation of attacks.

Al-Shihri, listed among Saudi Arabia's 85 most wanted terrorists in February 2009, was freed from the U.S. detention facility in Cuba in 2007 and passed a Saudi rehabilitation program for former jihadists before resurfacing with AQAP.

BBC security correspondent Frank Gardner wrote the death of al-Shihri would be "a serious but not fatal blow" for the militant network's operations.

"Saeed al-Shihri was not considered by Washington to be the most dangerous member of al Qaeda in Yemen," Gardner wrote. "That person is Ibrahim Hassan Tali al-Asiri, the Saudi bombmaker who sent his brother to Jeddah with a concealed suicide device that intended, but failed, to assassinate the prince in charge of Saudi counter-terrorism."