"A small army" of police have surrounded the South Trenton home, according to state news website nj.com. Authorities familiar with the situation said that the man, who has barricaded the house, is suspected of killing his wife and one of their children, RT reported.
Police were called to the home at about 3:30 pm on Friday for a "well-being check," local media report. Once inside the home, police found the partially decomposed body of the man's wife.
The man is then reported to have pulled out a gun, signaling to police that he was taking his children hostage in the situation.
Neighbors told local media that the couple, who moved to the block two months ago, has four children. While two or three of the children are thought to be alive in the house, one was reportedly killed.
Negotiators from the city and the state are trying to get the man out of his house without a fight, Mercer County First Assistant Prosecutor Angelo Onofri said.
The stand-off continues.