The Somali terror group that killed more than 60 people in a Kenyan mall Saturday is now more prone to mount deadly attacks on targets outside Somalia, U.S. officials said. Al Shabaab, which has a larger U.S. contingent than any other al Qaeda offshoot, claimed, via Twitter, that five of the jihadis holding hostages at the mall are Americans from states including Minnesota, Missouri, Maine and Arizona. Senior U.S. officials said that the names released on Twitter do not match the list of people from the U.S. known to be affiliated with Al Shabaab. About 20 U.S. passport holders are in al Shabaab, a U.S. official said Monday. The terror group attempted to kill U.S. Rep. Donald Payne during a visit to Mogadishu in 2009, but he survived, unharmed.