Police defused Thursday a small bomb at the American University of Beirut, in what appeared to be the latest of a series of attempts to cause explosions in Lebanon, security officials said. An explosives expert defused a bomb of 200 grams of TNT that was found in a bag near an elevator in the Issam Fares Hall, a building off the main campus, said the official. The bomb was wired to a detonator and ready to explode, the official added. It was taken to a police barracks for investigation. Police are also looking into how the bomb got into the university, whose entrances are guarded by policemen and the university's own security guards.