Senior Muslim clerics said Thursday that an Afghan man on trial for converting from Islam to Christianity should be killed regardless of whether a court decides to free him. Abdul Rahman, a 41-year-old former medical aid worker, faces the death penalty for becoming a Christian under Afghanistan's Islamic laws. His trial, which began last week, has caused an international outcry. US President George W. Bush said Wednesday he was "deeply troubled" by the case and expects the country to "honor the universal principle of freedom." Diplomats say the Afghan government is searching for a way to drop the case, and on Wednesday authorities said Rahman is suspected of being mentally ill and would undergo psychological examinations to see whether he is fit to stand trial. But four senior clerics interviewed by The Associated Press in their mosques in Kabul said Rahman deserved to be killed for his conversion.