(FILES) A file photo taken on February 13, 2017 shows a flyer during a protest outside the Iranian embassy in Brussels for Ahmadreza Djalali, an Iranian academic detained in Tehran for nearly a year and reportedly sentenced to death for espionage. – Western governments face an increasingly delicate dilemma over how to secure the release of foreigners and dual nationals detained in Iran, with activists accusing Tehran of engaging in “hostage” diplomacy by seeking exchanges. Iran has over the last years repeatedly detained foreigners and dual nationals on charges campaigners and governments say are unfounded, with the prisoners only going free after months and sometimes even years of painstaking negotiation. (Photo by DIRK WAEM / Belga / AFP) / Belgium OUT