A 66-year-old man was fatally shot by his elderly brother in an apartment they shared in Queens on Saturday, cops and sources said.

Jethro Jacobs, 73, allegedly shot his brother George Jacobs in the chest in the heat of a dispute at 7:40 a.m. in their apartment on 230^th Place in Laurelton, according to sources. Jethro Jacobs allegedly told cops George had pulled a knife on him first, sources added.

The victim was taken to Jamaica Hospital Medical Center and later pronounced dead, cops said.

The alleged gunman is now facing charges of murder and criminal possession of a weapon, according to police.