Three people were shot to death and two others were wounded Saturday in what authorities say was a targeted attack at an apartment.

Police responding to reports of gunfire around 4:30 a.m. in the city's Vailsburg section discovered the three dead in the apartment, which was engulfed in flames. They had been shot multiple times.

Killed were Sandra Bellush, 42, a tenant in the apartment; Brielle Simpkins, 15, of Elizabeth; and Eric Jackson, 19, of Newark.

Police also found a 17-year-old boy and a 20-year-old man at the building, but it was not clear if they were in the apartment. They were identified only as Newark residents.

Both were taken to University Hospital. A hospital spokesman said the teenager was treated for a single gunshot wound and released, while the man, who was shot several times, remained in fair condition Saturday afternoon.

Authorities said they believed the shootings were carried out by more than one assailant. The victims did not appear to be blood relatives, they said.

There were no signs of robbery or forced entry into the building, a house that had been converted into apartments, Essex County Prosecutor Paula Dow said.

A dog and a cat were also shot to death, Dow said.

"This was a targeted attack by heinous individuals," Mayor Corey Booker said at a news conference. "This is Newark, New Jersey, and this is not acceptable."

Arson investigators think the fire was intentional, said Paul Loriquet, a spokesman for the prosecutor's office.

"They're quite sure the fire was set to cover up the shootings," he said.

The rest of the building suffered minor damage.

The shootings brought to 77 the number of slayings in Newark, a city of about 280,000.

Dow and Booker said the building had no history of drug activity. A former resident of the neighborhood echoed that assessment.

"It's not a drug area, a high-crime area," said Harcourt Lucious, who used to live a few blocks from the building before moving to nearby Irvington. "This is an odd place for something like this to happen."