For story suggestions please contact tips@nma.com.twbr Officials are looking into an explosion that went off in central Prague on Monday. The building, which included an office of the International Air Transport Association and an art gallery, was a few dozen meters from Prague's National Theater.br br Authorities say 15 people were inside the building at the time of the blast, which officials suspect was caused by gas. The explosion was heard as far as Prague Castle, about 1.6 kilometers across Vltava river.br br The explosion blew out the windows of adjacent buildings and injured at least 40 people nearby.br br No deaths were reported, but about a dozen people were trapped inside the building after the explosion, and officials evacuated other buildings in the area as an investigation took place.