Fierce flames sent four firefighters to hospital after a fast-moving fire broke out in an East Harlem apartment building early Saturday morning. The fire, at a four-story building on Second Avenue between 103th and 104th Streets, also left several people without a place to live. Four civilians suffered minor injuries. It started in the ground floor deli. Firefighters said the windows were blown out upon their arrival and grew to four alarms. "The fire got into those voids. It traveled all the way to the top floor and in above that into the cockloft area between the top floor and the roof, and made it very difficult to get ahead of and fight. It was a stubborn fire," said Joseph Ferrante, FDNY deputy chief. The Red Cross was on the scene helping those displaced. The cause of the blaze is under investigation.