Pope Benedict XVI has urged the president of Afghanistan to pardon an Afghan man who risks execution for converting to Christianity, the ANSA news agency reported Saturday. The pontiff's request came in the form of a letter written by the Vatican's No. 2 official, Cardinal Angelo Sodano, ANSA said without citing sources. A Vatican spokesman could not immediately confirm the report. President Hamid Karzai has been under mounting pressure from foreign leaders to free Abdul Rahman, who faces a possible death sentence for alleged apostasy. Top officials in Afghanistan have said Rahman will be released soon, but clerics have questioned Karzai's authority to order his release and have warned of a possible revolt if he tries. Rahman is being prosecuted under Afghanistan's Islamic laws for converting 16 years ago while working as a medical aid worker for an international Christian group helping Afghan refugees in Pakistan. Countries that have demanded Rahman's release include Britain and the United States. Diplomats have said the Afghan government is searching for a way to drop the case without inflaming tensions here. Authorities said Rahman is suspected of being mentally ill and would undergo psychological examinations to see whether he is fit to stand trial.