Three people were shot — at least two of them teenagers — after gunfire erupted at a party in a Brooklyn backyard Saturday night.

The victims were attending a party behind 264 Essex St. in Cypress Hills when a group of suspects showed up and opened fire around 11:30 p.m., police said.

A 15-year-old boy was shot in the left leg and another male victim was shot in the right arm behind the residential building, according to the NYPD.

A 16-year-old boy was also shot in the right arm yards away at the corner of Atlantic Avenue and Essex Street, police said.

The two victims that were shot at the party were taken to Brookdale Hospital and the other victim was taken to Cohen Children’s Medical Center, according to officials, who said they were all expected to survive.

A group of suspects were being questioned by detectives in connection with the violence.

Two of the victims have rap sheets with the NYPD, sources said.