The incident began just before midnight in a Sellersville Heights Housing building in the 600 block of East Ridge Avenue.
Police say a brawl broke out in the H building.
They say one of the people involved in the fight then fled to the A building.
That suspect, believed to be armed, detained several people inside one of the apartments.
Police and SWAT teams surrounded the building for about an hour.
The situation ended peacefully. No weapon was found.
One person involved in the brawl was treated for cuts and bruises.
An investigation is underway.