A top Al Qaeda leader whose links stretch from Usama bin Laden's training camps to extremist networks in Europe has been captured in Pakistan, a U.S. law enforcement official confirms for the first time.

Pakistani officials also tell The Associated Press that Mustafa Setmarian Nasar, a dual Syrian-Spanish national with a $5 million U.S. bounty on his head, has been flown out of the country to an unspecified location.

Nasar was captured in a November sting in the southwestern Pakistani city of Quetta that left one person dead, the American official said on condition of anonymity because of the sensitivity of the matter. The official spoke to the AP late last week.

CountryWatch: Pakistan

U.S. military officials aware of the detention of terror suspects at American prison facilities in Bagram, Afghanistan, and Guantanamo Bay, Cuba, had no immediate information Tuesday on whether Nasar had been incarcerated at either jail.

A senior Pakistani intelligence official told the AP from the capital, Islamabad, that Nasar was flown out of Pakistan to an undisclosed destination "some time ago."

"I only know that he is not here. But, I do know that Syrian authorities had also requested to get him back," said the official, who spoke on condition of anonymity because of the sensitive nature of his work.

Pakistani and American officials have long been tightlipped on the status of Nasar. He has been described by the U.S. Justice Department as a former trainer at bin Laden's camps in Afghanistan who helped teach extremists to use poisons and chemicals.

Another Pakistani official confirmed the Quetta arrest but had no information on Nasar's whereabouts.

"He had been interrogated by us. He had been interrogated by our American friends," said the official, who also declined to be identified because of the secretive nature of his activities.

He added that both Syrian and U.S. authorities wanted to take Nasar into custody.

A picture and short biography of the red-haired Nasar was recently removed from the U.S. government's Rewards for Justice Web site. Justice and State Department officials declined to say why Nasar was no longer profiled.

It would not be the first time Pakistan -- a key U.S. ally in the war against terrorism -- has detained Al Qaeda terrorists and turned them over to the Americans.

Pakistan says it has captured more than 750 Al Qaeda suspects since the Sept. 11 attacks and has handed most of them to the United States.

They include Al Qaeda's former No. 3, Khalid Shaikh Mohammed -- a key planner of the attacks who was arrested in March 2003 during a raid near Islamabad -- and his purported replacement, Abu Farraj al-Libbi, who was detained in May 2005 in Pakistan's northwest.

Media reports have linked Nasar, who holds Spanish citizenship, to the 2004 commuter train bombings in Madrid that killed 191 people, and to the July 7 attacks in London that left 56 dead, including the four bombers.

In September 2003, Nasar was among 35 people named in a Spanish indictment for terrorist activities connected to al-Qaida. His exact role, if any, to either the Madrid or London bombings is unclear.

He is also wanted for a 1985 attack on a restaurant near a military base close to Madrid airport that left about 20 people dead -- regarded as the first international Islamic terrorist attack to take place in Spain.

Spain's ambassador to Pakistan, Jose-Maria Robles, said Spain had sought information from Pakistan about Nasar's reported arrest in November but had received no reply.

"Pakistan knows our interest but we have not had any official answer," he said in Islamabad on Tuesday.

Nasar, who lived in Spain and was married to a Spanish woman, also stayed in London during the mid-1990s before traveling to Afghanistan, where he was believed to have been part of bin Laden's network, a Western diplomat in Islamabad said.

His movements have been traced to Syria, Afghanistan, Iran, Iraq and at least two European capitals.

Singapore-based terrorism expert Rohan Gunaratna said Nasar's capture is a major blow to the Al Qaeda movement because he was the "most prolific writer" of jihadi propaganda and held close links with extremists throughout Europe and South Asia.

"The ideologues are as equally important as the operational people and he was in close contact with very prominent figures with movements in different countries, particularly the North African region," Gunaratna said.

In 2004, Nasar released a 1,600-page book titled "The International Islamic Resistance Call," which lays out strategies for attacking Islam's enemies.