WASHINGTON -- More than half a dozen senior leaders of Osama bin Laden's al-Qaida network and several hundred of his most loyal fighters have been killed in the war in Afghanistan so far, U.S. officials say.
Al-Qaida is the top American target in the war, and the military's focus on its leaders has severely hurt bin Laden's ability to communicate both in Afghanistan and with terrorists overseas, U.S. intelligence officials say.
But thousands of al-Qaida fighters are still alive in Afghanistan, believed to be mixed in with Taliban fighters and willing to fight on. And a second rank of leaders is stepping in to take the place of top bin Laden lieutenant Mohammed Atef and others eliminated in the U.S. bombing.
"The question is, 'What's the depth of their bench?' and that we don't know," said Daniel Benjamin, a former National Security Council staffer and terrorism expert now with the Center for Strategic and International Studies.
Moreover, al-Qaida terrorists outside Afghanistan may still be capable of proceeding with planned attacks, even if they're unable to communicate with leaders still inside Afghanistan, officials warn.
On Wednesday, the U.S. military continued to focus on targeting top leaders, after bombing on Tuesday damaged a compound near the southern stronghold of Kandahar believed used by senior Taliban or al-Qaida figures, the Pentagon said. It was unclear if any were killed, officials said.
"There will always be pockets that are going to fight to the death," said Rear Adm. John Stufflebeem. "But getting the leadership and breaking the chain of command is going to render much of that ineffective."
Between 4,000 and 5,000 foreign fighters with ties to bin Laden's al-Qaida network were believed to have been in Afghanistan when the United States began bombing on Oct. 7. In most cases, they blended in with Taliban from Afghanistan.
Several hundred of the al-Qaida rank-and-file have been killed during U.S. airstrikes and ground fighting, said one U.S. official, speaking on the condition of anonymity. In addition, the military has tallied the deaths of seven al-Qaida leaders and senior aides, said a defense official.
The most significant so far was Mohammed Atef, one of the top two advisers to bin Laden, who was killed in a CIA-assisted U.S. airstrike around Nov. 14. Atef was bin Laden's operational planner and believed to have supervised planning for several attacks, including the Sept. 11 attacks on the World Trade Center and Pentagon.
Two other bin Laden lieutenants, security chief Sayf al-Adl and aide Abd al Aziz al-Jamal, are believed to be taking over Atef's duties.
Two others considered in al-Qaida's "top 20" are believed dead after U.S. bombing in early November near Khowst, near the Afghan-Pakistan border, military and other officials said. They were identified as Mohammed Salah and Tariq Anwar al-Sayyid Ahmad, both from Egypt.
The remaining thousands of al-Qaida fighters comprise many of the pockets of resistance in the countryside, with concentrations east of Kandahar and south of Kabul, U.S. officials said.
Others, captured in the fall on Kunduz, led the prison uprising at Mazar-e-Sharif that left a CIA officer dead, officials said. Al-Qaida fighters are driving Taliban who would otherwise be ready to surrender to continue to resist out of fear of al-Qaida reprisals.
The attacks on al-Qaida fighters and the northern alliance's battlefield success have made it increasingly difficult for al-Qaida leaders to communicate both within Afghanistan and with cells outside of the country, a U.S. official said. Orders aren't being relayed, money isn't being transferred and operational planning has been slowed.
Al-Qaida is known to use everything from satellite phones to couriers to send messages.
"Osama is not able to communicate in any meaningful way abroad," said Vince Cannistraro, a former CIA counterterrorism chief.