Bullets flew across the Big Apple Saturday morning, leaving one man dead and two others hurt in three boroughs, cops said. 

Gunfire erupted just before 6 a.m. at 3700 Jerome Ave in the Bronx when a 45-year-old man was fatally shot in the head, cops said.

The victim was rushed to Montefiore Medical Center where he died, cops said.

The man’s identity was pending family notification.

There were no arrests.

A revolver was recovered nearby, cops said.

The manager at nearby Gino’s Pizza and Restaurant said he had just gotten to work and was in the back cooking when a man came in and told him someone had fallen from a building out front.

“He told me, he said, ‘I saw one guy fall,’” said the manager, who refused to provide his name.

“I go to the front and the guy’s on the floor already.”

He said he called 911.

“Right now the police is coming over here every day,” the worker said.

“These people have no respect. Drugs, fights, shooting, everything.

“It is very dangerous.”

A homeless man who declined to give his name said he heard three shots fired last night around 11 p.m. 

“Boom, boom, boom, like real heavy,” he said.

“That’s a heavy gun right there. It came from up top at the station.”

Another homeless man who declined to give his name said he found the victim around 5 a.m. on the ground. 

“At 5 a.m., I seen a man on the ground and he was bleeding out his mouth,” the man said.

“He had on a hoodie. I pulled the hood back and I saw blood on him. He had no bullet holes, but I saw on the side of his face that something had happened to him.

“He was still breathing. We waived down the police.”

A police spokeswoman said she had no information about the victim falling and that police found the man when they responded to a 911 call.

A few hours earlier, an 18-year-old man male was shot in the back near 144 Center Street in Brooklyn around 2:22 a.m.

The teen was rushed to Methodist Hospital in stable condition.

He told investigators two unknown males attacked him and that one of them shot him, according to cops.

Then, at 2:30 a.m., a 31-year-old man was blasted in the gut in front of a convenience store at East 116th Street and Lexington Avenue in East Harlem, cops said.

The man was rushed to Harlem Hospital in stable condition.

The victim told investigators he didn’t know who shot him and was uncooperative, according to police.

On Friday evening, a 38-year-old man was fatally shot in the torso at 2020 Albemarle Road in Flatbush, Brooklyn, cops said.

EMS rushed Winston Chee to Kings County Hospital, where he died, cops said.