Iranian authorities Thursday executed a teenager convicted of setting fire to a security forces base during January protests, as the Islamic republic ramps up executions during the war with the US and Israel, rights groups said.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.