Japanese police were investigating a suspected extremist attack on the U.S. Army after two small explosions outside a military base south of Tokyo, according to AP. There were no reports of injury or damage, and no one claimed responsibility, police said today. Investigators found a pair of metal tubes _ apparently improvised rocket launchers aimed toward the Camp Zama base _ at a nearby park, said Kanagawa prefecture (state) police spokesman Hiroyoshi Ichikawa. Ichikawa said that further details were not immediately known, and that police were trying to identify the suspects.