An explosion erupted in a residential building early Tuesday, killing five people and injuring nine, the Rio de Janeiro emergency services said.

Rio's fire department said the explosion happened at a housing project in Coelho Neto, a poor neighborhood in the city's north. The first floor of the five-story building was heavily damaged in the blast and windows in nearby buildings were shattered.

The fire department declined to comment on what might have caused the blast. Neighbors told local media they had reported the smell of gas leaks for more than a year.

Gas-related explosions are a relatively frequent occurrence in Rio de Janeiro, a city of 12 million people.