It happened just before 2:50 a.m. at the Delta Hotels by Marriott in Woodbridge, Middlesex County.
Our sister station WABC-TV reports four people were rushed to Robert Wood Johnson University Hospital in New Brunswick. Their conditions are not yet known.
"I heard four shots, actually five; I heard running scattering all over," a hotel guest said. "I stayed here before prior, the night before and it was fine, room 125 was fine, but then last night I stayed in 227 and it was uncomfortable."
Police are interviewing witnesses who were part of a large group at the hotel when the violence broke out.
Middlesex County Prosecutor Yolanda Ciccone said, "I can confirm my office and Woodbridge PD are investigating a shooting. Details to follow."
No arrests have been made.