A suspected al-Qaida operative who lived for more than 15 years in the US has become chief of the terror network's global operations, the FBI says, marking the first time a leader so intimately familiar with American society has been placed in charge of planning attacks.

Adnan G. Shukrijumah. is seen in these artists renderings by the FBI and made available to the Associated Press Aug. 2, 2010. [Agencies]

Adnan Shukrijumah, 35, has taken over a position once held by 9/11 mastermind Khalid Sheikh Mohammed, who was captured in 2003, Miami-based FBI counterterrorism agent Brian LeBlanc said. That puts him in regular contact with al-Qaida's senior leadership, including Osama bin Laden, LeBlanc said.

Shukrijumah (SHOOK'-ree joohm-HAH') and two other leaders were part of an "external operations council" that designed and approved terrorism plots and recruits, but his two counterparts were killed in US drone attacks, leaving Shukrijumah as the de facto chief and successor to Mohammed -- his former boss.

"He's making operational decisions is the best way to put it," said LeBlanc, the FBI's lead Shukrijumah investigator. "He's looking at attacking the US and other Western countries. Basically through attrition, he has become his old boss."

The FBI has been searching for Shukrijumah since 2003. He is thought to be the only al-Qaida leader to have once held permanent US resident status, or a green card.

Shukrijumah was named earlier this year in a federal indictment as a conspirator in the case against three men accused of plotting suicide bomb attacks on New York's subway system in 2009. The indictment marked the first criminal charges against Shukrijumah, who previously had been sought only as a witness.

Shukrijumah is also suspected of playing a role in plotting of potential al-Qaida bomb attacks in Norway and a never-executed attack on subways in the United Kingdom, but LeBlanc said no direct link has yet emerged. Travel records and other evidence also indicate Shukrijumah did research and surveillance in spring 2001 for a never-attempted plot to disrupt commerce in the Panama Canal by sinking a freighter there, LeBlanc said.