An improvised Palestinian military court on Thursday sentenced four Palestinians to prison for the assassination last year of Israel's tourism minister, a Palestinian security official said. The four were sentenced by a tribunal in Palestinian leader Yasser Arafat's besieged headquarters in Ramallah. The sentences ranged from one to 18 years, the official said. The man convicted of killing Rechavam Ze'evi received an 18-year prison term, while a driver and a lookout were sentenced to 12 and eight years, respectively. A Palestinian who was convicted of knowing about the plot but took no active role in the killing received a one-year sentence.