WASHINGTON Al-Qaedas third-ranking leader, who was a founding member of the militant group, has been killed in Pakistan, according to US media reports Tuesday. The Washington Post said that the news of the death of Mustafa Abu al-Yazid, also known as Sheik Saeed al-Masri, came in a statement Monday from al-Qaeda that US intelligence officials believe is accurate. A US official said there is strong reason to believe that al-Masri, an Egyptian, was killed, apparently by a CIA drone strike in Pakistans tribal belt within the past two weeks. The official described it as a significant victory against the terrorist group. Al-Masri was the groups chief operating officer, with a hand in everything from finances to operational planning, the official said. He was also the organisations prime crony to bin Laden and Zawahiri, he added, referring to al-Qaedas No 2 leader, Ayman al-Zawahiri. He was key to al-Qaedas command and control. Yazid, 54, was an original member of al-Qaedas Shura leadership council and had served as an adviser to Osama bin Laden for more than 15 years. More recently, he served as al-Qaedas chief organisational manager, in charge of its finances and logistics, as well as a liaison to the Taliban and other extremist groups. Yazid was part of the Egyptian contingent that has dominated al-Qaedas leadership since the networks founding. He and Zawahiri served time in prison in the early 1980s for their role as conspirators in the 1981 assassination of Egyptian President Anwar Sadat. Previous reports of Masris death proved unfounded. But the US official said the latest reports appear accurate. In terms of level of confidence, its very high, the official said.