Dozens of Liberian immigrants mourned Saturday at a house where seven members of their community died in a fire that a survivor said started when a kerosene heater spilled fuel and exploded as it was being moved outdoors. Authorities have not released the names of all the victims, but fire survivor Harris Murphy said those trapped in the basement blaze were part of the large Liberian enclave in southwest Philadelphia. The blaze broke out around 10:45 p.m. Friday in a three-story brick duplex and killed three adults and four children, including a 1-year-old boy, fire department spokesman Chief Daniel Williams said. Fire officials said six victims were found huddled together in the front of the basement, one of them cradling the baby. The seventh was found near the basement door.