The Fire Department is stressing the importance of smoke detectors after determining that matches and candles caused two deadly fires over the weekend that killed seven people, including four children.

Fire officials confirmed this morning that the fire in Brooklyn early Sunday that left a man and his nephew dead was sparked by a lit candle.

Simeon Frasier, 12, and his 33-year-old uncle, Sean Monderson, died when flames engulfed the third-story apartment.

According to the Daily News, Fire Department officials were unsure if there were any smoke detectors in the entire building.

Officials also determined this morning that a Saturday's deadly Manhattan fire was caused by a child "playing with a lighter or matches."

On Saturday morning, flames ripped through a sixth-floor apartment in the Robert Fulton Houses on 18th Street and 9th Avenue in Chelsea, killing Maschay Joa Valdez, Delkis Balbuena and three of their four children.

Firefighters say the apartment's smoke detector was unplugged and the backup battery was removed.

A fourth child, a 10-year-old boy, was taken to the hospital in critical condition.