BRUSSELS (Reuters) - Belgian prosecutors said on Thursday they had detained a man of Iraqi nationality after a series of letters containing a nerve gas ingredient were sent to the prime minister's office and the U.S. and British embassies. A spokeswoman for the federal prosecutor's office told a news conference the 45-year-old man was arrested late on Wednesday in the western Belgian town of Deinze. Two postal workers were taken to hospital after being exposed to the chemicals in the letters at mail depots. No one else was hurt by the 10 letters sent to a variety of targets, including...