A maniac slashed three elderly people with a machete in an unprovoked attack and was fatally shot by cops at Grand Central Terminal Saturday morning — causing mayhem that sent panicked commuters fleeing the iconic station, police and witnesses said.

An 85-year-old man and a 65-year-old man were slashed in their heads on the 4, 5, 6 subway platform at the iconic station at 9:50 a.m., police said. A 70-year-old woman was also slashed, but it wasn’t clear where on her body, cops said.

Blood-soaked white gauze was wrapped around one victim’s head, photos from the scene show. The slasher appeared to be naked, but it wasn’t clear if his clothes were removed by emergency workers after he was shot.

Two NYPD detectives, who were working overtime to provide transit security, confronted the 44-year-old man and told him to drop the machete.

The slasher, identified as Anthony Griffin, ignored their commands and was shot three times, according to police sources.

The victims were taken to local hospitals in stable condition, cops said.

Griffin was taken to Bellevue Hospital and was pronounced dead a short time later, cops said.

He has 13 prior arrests, including one for menacing with a sharp object, police sources said.

The two officers were taken to the hospital for treatment of tinnitus, cops said.

Mayor Zohran Mamdani said in a post on X that he was “grateful to the NYPD for their quick response and for preventing additional violence.”

“The NYPD is conducting an internal investigation and will release body-worn camera footage, as it does in all incidents involving the discharge of an officer’s firearm,” he said.

Claudio Delgado, 53, was in the main hall of Grand Central when the chaos erupted after getting off his train from Connecticut to visit his mother in the hospital.

“I was coming from Connecticut when ‘Boom!’ everyone got down on the floor fast,” the 53-year-old said. “Then the police said, ‘Get outta here! Get outta here fast!’ They said it was somebody with a gun and police were involved too. It’s scary. This is how New York City is now. It’s too much violence in New York City now.”

A worker at the station, who declined to give his name, was also rattled.

“I saw them [paramedics], they came up with somebody on the stretcher, and they were pumping his chest,” he said. “It’s crazy. You could be on the platform minding your business, and someone had a machete, it’s scary, scary, scary.”

Worker Jessica Munoz, who’s employed at the Bourke Street Bakery near the subway entrance, saw people running out of the station at East 42nd Street and Lexington Avenue.