In a posting on Islamist websites late Thursday, Zawahiri demanded that all Al Qaeda and Taliban prisoners held throughout the world be released in exchange for Warren Weinstein, who was seized Aug. 13 in an upscale neighborhood in the eastern city of Lahore. Zawahiri also said the U.S. must cease its air attacks against Islamic extremists in Afghanistan, Pakistan, Somalia and Yemen, and warned the Weinstein family against trusting President Obama.
The U.S. State Department is aware of the statement and continues to work with Pakistani authorities leading the investigation, a spokeswoman said.
Weinstein was abducted two days before he was to move back to the U.S. after living in Pakistan for seven years. He was Pakistan country director for the consulting firm J.E. Austin Associates, which often works with the U.S. Agency for International Development, the American government's primary international aid organization.
The company website listed Weinstein as an expert in international development and proficient in six languages. His areas of expertise include governance, microfinance, small and medium-size business development and institutional development.
The company has said Weinstein is in poor health, and it released a list of medications, many for heart-related problems, imploring the kidnappers to make them available to him.
Pakistani police in August raided a house in the central Pakistani town of Khushab where they believed Weinstein was being held, but the kidnappers had fled with the American before police arrived, Lahore authorities said.
Police and U.S. officials have never publicly said who they believed was holding Weinstein, but Islamist militant groups were the main suspects.
-- Times staff and wire reports
Photo: Ayman Zawahiri, in a still photo taken from video released Dec. 1, 2011, claims that Al Qaeda was behind kidnapping of 70-year old American Warren Weinstein in Pakistan. "Just as the Americans detain all whom they suspect of links to Al Qaeda and the Taliban, even remotely, we detained this man who is neck-deep in American aid to Pakistan since the '70s," Zawahiri said, according to a translation.