Iranian students heckled Iranian President Mohammad Khatami today, accusing him of failing to deliver promised democratic reforms in the country.The incident occurred as Khatami was trying to make an address marking Iran's annual Student's Day at Tehran University. Reports say some 300 out of a crowd of some 1,500 students jeered and shouted insults at Khatami, causing him to interrupt his speech. He then threatened to have the hecklers removed from the audience and proceeded to defend his political record against the crowd. Khatami, who is nearing the end of his second and final term as president, was once a key figure for the Iranian reformist student movement. Student's Day in Iran commemorates the killing of three students in 1953 who were protesting against a visit of then U.S.-vice president Richard Nixon.