After more than five years of trying to hunt down and eliminate al Qaeda's leaders, U.S. intelligence officials are dismayed that new ones are emerging. The article makes the point that Iraq will provide the next generation after that -- and they'll be darned good terrorists.

Some excerpts from the NYT story:

American, European and Pakistani authorities have for months been piecing together a picture of the new leadership, based in part on evidence-gathering during terrorism investigations in the past two years. Particularly important have been interrogations of suspects and material evidence connected to a plot British and American investigators said they averted last summer to destroy multiple commercial airlines after takeoff from London.

Intelligence officials also have learned new information about Al Qaeda’s structure through intercepted communications between operatives in Pakistan’s tribal areas, although officials said the group has a complex network of human couriers to evade electronic eavesdropping.

The investigation into the airline plot has led officials to conclude that an Egyptian paramilitary commander called Abu Ubaidah al-Masri was the Qaeda operative in Pakistan orchestrating the attack, officials said.

Mr. Masri, a veteran of the wars in Afghanistan, is believed to travel frequently over the rugged border between Pakistan and Afghanistan. He was long thought to be in charge of militia operations in the Kunar Province of Afghanistan, but he emerged as one of Al Qaeda’s senior operatives after the death of Abu Hamza Rabia, another Egyptian who was killed by a missile strike in Pakistan in 2005.

The evidence officials said was accumulating about Mr. Masri and a handful of other Qaeda figures has led to a reassessment within the American intelligence community about the strength of the group’s core in Pakistan’s tribal areas, and its role in some of the most significant terrorism plots of the past two years, including the airline plot and the suicide attacks in London in July 2005 that killed 56. ....

Officials say they believe that, in contrast with the somewhat hierarchical structure of Al Qaeda in Afghanistan before Sept. 11, the group’s leadership is now more diffuse, with several planning hubs working autonomously and not reliant on constant contact with Mr. bin Laden and Ayman al-Zawahri, his deputy.

Much is still not known about the backgrounds of the new Qaeda leaders; some have adopted noms de guerre. Officials and outside analysts said they tend to be in their mid-30s and have years of battlefield experience fighting in places like Afghanistan and Chechnya. They are more diverse than the earlier group of leaders, which was made up largely of battle-hardened Egyptian operatives. American officials said the new cadre includes several Pakistani and North African operatives.

Experts say they still see Al Qaeda in Mesopotamia as largely independent of Al Qaeda’s hub in Pakistan but that they believe the fighting in Iraq will produce future Qaeda leaders.

“The jihadis returning from Iraq are far more capable than the mujahedeen who fought the Soviets ever were,” said Robert Richer, who was associate director of operations in 2004 and 2005 for the C.I.A. “They have been fighting the best military in the world, with the best technology and tactics.”

Officials said other operatives believed to be plotting internationally are Khalid Habib, a Moroccan, and Abdul Hadi al-Iraqi. Mr. Iraqi, a Kurd who served in Saddam Hussein’s army, moved to Afghanistan to fight Soviet occupiers. Officials believe that he was dispatched to Iraq by Mr. bin Laden to deal with Abu Musab al-Zarqawi, whose terrorist group allied with Mr. bin Laden. It took the name Al Qaeda in Mesopotamia before Mr. Zarqawi was killed in an American bombing in June of last year. American officials say they believe that Mr. Iraqi is now back operating inside of Pakistan.

Officials are also divided and somewhat puzzled about Iran’s role in pursuing Qaeda figures.

Intelligence officials say they believe that the Iranian government has in some cases been quite active in the hunt and has put under house arrest a number of top operatives who fled from Afghanistan after the Sept. 11 attacks, including the Egyptian operations chief Saif al-Adel and Saad bin Laden, one of the Qaeda leader’s sons.

But officials say they believe that several other important Qaeda figures may be operating in Iran, including an Egyptian known as Abu Jihad al-Masri and a Libyan explosives expert named Atiyah Abd al-Rahman, who is thought to travel between Iran and Pakistan’s tribal areas.