WASHINGTON (AFP) - The United States reportedly has secret contingency plans to safeguard Pakistani nuclear weapons if they risk falling into the wrong hands. But US officials worry their limited knowledge about the location of the arsenal could pose a problem, the Washington Post said, a week after Pakistani President Pervez Musharraf declared a state of emergency. "We can't say with absolute certainty that we know where they all are," one unidentified former US official told the newspaper, adding that any US effort to secure Pakistan's nuclear arsenal "could be very messy." Under a more optimistic scenario, the Pakistani military...