WASHINGTON (AFP) - Qaeda is holding a US aid worker captured last August in Pakistan, the group's leader Ayman alZawahiri said in a statement seen Thursday by a monitoring group. Zawahiri said Qaeda had abducted USAID worker Warren Weinstein, who is neck-deep in American aid to Pakistan, on August 13 from Lahore, and that the White House has the ability to get him freed if it halts US airstrikes and releases prisoners including relatives of Osama bin Laden, the SITE Intelligence Group said.