Four Japanese citizens have been arrested in Iran in the past three months on charges of trying to smuggle drugs out of the country, the head of the nation\'s police anti-narcotics unit said on Sunday. \"These individuals obtained manufactured drugs in Iran and were seeking to transport them to another country when they were arrested. A large amount of drugs was seized,\" General Ali Movayedi was quoted by Iranian media telling a news conference. He did not give further details about the Japanese suspects, the dates they were arrested or their fate, or if they were travelling separately or together. The Japanese embassy in Tehran told AFP it was seeking to verify the information. Iran often imposes the death penalty for convicted drug traffickers. According to Amnesty International, the Islamic republic last year executed at least 360 people, three-quarters of them for drugs offences.