FP:

Secretary-General António Guterres is making a quiet appeal to Iran’s leaders to release an elderly American citizen detained on what the U.S. claims are trumped up charges of espionage, according to several officials.

Guterres, a former Portuguese prime minister and U.N. refugee chief, wrote a highly confidential letter a week ago to the Iranian president, Hassan Rouhani, to ask for the release on humanitarian grounds of Baquer Namazi, an 81-year-old retired UNICEF official.