WASHINGTON - When al-Qaida's No. 2 leader Ayman al-Zawahiri called off a planned chemical attack on New York's subway system in 2003, he offered this chilling explanation: The plot to unleash poison gas on New Yorkers was being dropped for "something better," Zawahiri said in a message intercepted by U.S. eavesdroppers.
The meaning of Zawahiri's cryptic threat remains unclear more than six years later, but a new report warns that al-Qaida has not abandoned its goal of attacking the United States with a chemical, biological or even nuclear weapon.
The report, by a former senior CIA official who led the agency's hunt for terrorists' weapons of mass destruction, portrays al-Qaida's leaders as determined and patient, willing to wait for years to acquire the kinds of weapons that could inflict widespread casualties.
The former official, Rolf Mowatt-Larssen, draws on his knowledge of classified case files to argue that al-Qaida has been far more sophisticated in its pursuit of weapons of mass destruction than is commonly believed, pursuing parallel paths to acquire weapons and forge alliances that can offer resources and expertise.
"If Osama bin Laden and his lieutenants had been interested in . . . small-scale attacks, there is little doubt they could have done so now," he writes in a report released yesterday by Harvard University's Belfer Center for Science and International Affairs.
The report comes as a panel on weapons of mass destruction appointed by Congress prepares to release a new assessment of the federal government's preparedness for such an attack. The review by the bipartisan Commission on the Prevention of Weapons of Mass Destruction Proliferation and Terrorism is particularly critical of the Obama administration's actions so far in hardening the country's defenses against bioterrorism, said two former government officials who have seen drafts of the report.
The commission's initial report in December 2008 warned that a terrorist attack using weapons of mass destruction was likely by 2013.
Mowatt-Larssen, a 30-year CIA veteran, led the agency's internal task force on al-Qaida and weapons of mass destruction after the 9/11 attacks and later was named director of intelligence and counterintelligence for the Energy Department.