Iranian authorities Thursday executed a teenager convicted over January protests after a fast-track trial rights groups labelled as "grossly unfair", as the Islamic republic ramps up executions during the war with the US and Israel.Amir Hossein Hatami, 18, was sentenced to death in February along with six others by a Tehran revolutionary court and was hanged at dawn in the notorious Ghezel Hesar prison outside the capital, according to Norway-based NGO Iran Human Rights.