Police were called to the home before 3 p.m. Friday on reports that a man had barricaded himself inside.
Authorities said police entered the home and found the man brandishing a gun. Police retreated safely, and a SWAT team was called in. Police also had a robot on scene Saturday ready to enter the home.
State Police Sgt. Adam Grossman said an arson bomb unit was also on the scene. Police declined to say whether the man was making any demands.
Homes on the surrounding block have been evacuated as a precaution, and police tape cordoned off the street in front of the house and nearby. An ambulance was parked near the home but left the scene earlier Saturday.
Lt. Mark Kieffer told The Times of Trenton that police had not been called to the home before.