At least six persons have been killed in a road accident near Moroccan city of Agadir, officials said.Two trucks running in the same direction collided on the Agadir-Marrakesh highway on Saturday, causing fire that burnt two other cars nearby, killing the six passengers in the cars, Xinhua news agency reported quoting the officials.Authorities, security and civil defence services, and the specialised technical services rushed to the scene to put out the fire and take necessary measures.An investigation has been launched to find out the reasons behind the accident.