BERLIN, Feb 13 (Reuters) - Images shot in the hold of a boat where dozens of people died of asphyxiation after five hours in the Mediterranean brought home the horror of the refugee crisis in the film "Fuocoammare" (Fire at Sea) shown at the Berlin film festival on Saturday. A theme of this year's festival is to encourage the world to help and welcome refugees. Director Gianfranco Rosi's harrowing two-hour documentary, which is in competition for the top Golden Bear prize, underscores the urgency of the problem. Rosi, whose "Sacro GRA" won the top prize at the Venice film festival in 2013, said his latest film "bears witness to a tragedy that's happening right in front of our eyes".