A 6-year-old boy was stabbed to death and a 7-year-old girl was seriously wounded when they were attacked by a maniac with a butcher knife while heading out to get a snack in Brooklyn.

Prince Joshua Avitto, 6, and Mikayla Capers, 7, were in an elevator together when they were hacked and stabbed multiple times in the random 6 p.m. attack, law-enforcement sources said.

“They were just coming outside to get some ice cream and ices,” said Inez Rodriguez, president of a tenants association. “This is the worst thing that I’ve ever seen in this neighborhood.”

The young boy was found dead in the elevator of the Boulevard Houses at 845 Schenck Ave. in East New York, sources said.

“They done killed my baby,” the little boy’s distraught mother said outside Brookdale Hospital.

“His birthday was in 16 days! Lord, they done killed my baby!”

The little girl, who was chased by the maniac out of the elevator on the first floor, collapsed in front of a nearby building, sources said. Mikayla was in surgery at Brookdale Hospital.

“What kind of animal would do a thing like this?” said Mikayla’s great-grandmother, Regenia Trevathan. “I have faith in the NYPD to pound the streets until they catch this bastard.”

The attacker fled after the fatal assault. Sources said the attack was random and a butcher knife was recovered at the scene.

Resident Kevin Velez, 41, said it was a peaceful Sunday until all hell broke loose.

“It was just a normal day with kids running around. And then it became chaos,” Velez said. “People running around and yelling. It’s hard for me to take.”

Velez said he witnessed Prince being taken out of the building.

“He was lifeless, just lifeless. I can’t get the image out of my head,” he said. “There was blood all over the front door. This is horrendous. The police need to catch this animal.”

The callous double stabbing took place two days after an 18-year-old girl died after being stabbed 32 times in the chest nearby in East New York, sources said.

Tayana Copeland was butchered just down the block on Stanley Avenue near Linwood Street at about 9:20 p.m. Friday.

Cops tonight cannot rule out a connection between the attack on the woman and the attack on the kids.

Additional reporting by Antonio Antenucci