Al Qaeda Claims to Be Holding U.S. Hostage in Pakistan

Al Qaeda claimed responsibility Thursday for the kidnapping of a 70-year-old American aid worker in Pakistan -- a claim that one U.S. official tells Fox News is "entirely possible," though it has not been confirmed.

In a video message posted on militant websites, Al Qaeda leader Ayman al-Zawahiri said Warren Weinstein would be released if the United States stopped airstrikes in Afghanistan, Pakistan, Somalia and Yemen. He also demanded the release of all Al Qaeda and Taliban suspects around the world.

Weinstein was abducted by armed men from his house in the eastern city of Lahore on Aug. 13.

"It's entirely possible that Al Qaeda or one of its militant allies may be holding Mr. Weinstein and the statement by Zawahiri supports this conclusion," the official told Fox News. "The documents from Bin Laden's hideout show his frustrated deputies were considering kidnapping and other criminal enterprises as a means of striking from their weakened state."

A translation of Zawahiri's message was provided by the SITE Intelligence Group, which monitors militant messages.

"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 1970s," Zawahiri said.

Police and U.S. officials have not publicly said who they believed was holding him, but Islamist militant groups were the main suspects.

Weinstein, who has a home in Rockville, Maryland, worked in Pakistan for several years and spoke Urdu.

He was the country director in Pakistan for J.E. Austin Associates, a U.S.-based firm that advises a range of Pakistani business and government sectors. The company has said Weinstein is in poor health and provided a detailed list of medications, many of them for heart problems, that it implored the kidnappers to give him.

Fox News' Catherine Herridge and The Associated Press contributed to this report.