At least 15 people were killed after a speedboat carrying Indian tourists capsized off Vietnam's southern Phu Quoc Island on Saturday, according to authorities.The speedboat was carrying 36 people when it capsized about 400 metres (440 yards) off May Rut Ngoai Islet, authorities said.Nearby tourist boats rushed to the scene after spotting the capsized vessel and joined rescue efforts. One boat owner involved in the operation said his vessel reached the site within about five minutes, but the rescue was complicated because several passengers were trapped inside the overturned boat."Only a few people were brought out conscious," the boat owner said, as cited by VN Express.He added that the sea off An Thoi was rough at the time, despite the absence of rain, while other tourist boats continued