Police shot people in three separate incidents across the city Thursday, killing a 78-year-old man in Brooklyn and wounding two others in Queens and the Bronx.

In the earliest reported confrontation of the unusually warm day, officers responded to a 911 call about a robbery at an address on Lewis Avenue in Bed-Stuy just after 1 p.m. The caller said his elderly uncle was inside, according to police officials.

When officers arrived and knocked on the door of the apartment in question, a man came out with a gun. Police said he pointed it at the officers, and ignored their shouts for him to stop. The officers both fired their guns, striking him several times. He later died at a local hospital, according to police.

Briefing reporters at the scene, NYPD Chief Jeffrey Maddrey called it “a tragic situation,” where “officers were put in a life and death situation investigating a crime in progress.”

The man, who police believe was the homeowner and the uncle from the 911 call, had no prior interactions with the NYPD. It was unclear if he ever fired his weapon. The officers were treated at a local hospital for minor injuries, including tinnitus.

Several hours later, around 3:40 p.m., officers in Queens shot a man who had allegedly stabbed a security guard in the stomach near the First Presbyterian Church on 164th Street in Jamaica.

Police were called to the area after a woman saw the man acting erratically in front of the church with a knife in his hand. She alerted a 40-year-old security guard, who approached the man and was allegedly stabbed.

Responding police officers called repeatedly for the man to drop his bloody knife, but he did not comply, according to NYPD Chief John Chell. As he waved at the cops and moved toward them with the weapon, they shot him twice and used a Taser.

"The actions of the security from the First Presbyterian Church, the administrative building that was occupied with many people, he did a great job in confronting the male with the knife and stopping maybe this male getting into that location and causing more damage," Chell said.

Police said they were aware of the man’s history of mental illness prior to the confrontation.

He and the security guard were both taken to a nearby hospital and listed in stable condition. The officers were also being treated.

Four hours later, just before 8 p.m., police in the Bronx were called to the elevated subway station on Broadway and West 238th Street after 911 callers described a man with a gun on the platform.

“The calls described a man acting crazy, waving a gun at a crowd which included children,” said NYPD Chief of Transportation Michael Kemper during a press conference at the scene — the third time on Thursday night that police would brief reporters.

When officers arrived, witnesses immediately pointed them toward the man. He refused commands to drop his gun and started walking south on the catwalk towards the 231st Street stop.

Kemper described how the officers called for backup and were able to “sandwich him in” on the catwalk.

There, cops said the man continued to ignore the officers, at times pointing his gun at them. One of the officers fired a round, striking the man in the left hand and causing him to drop the gun.

An Instagram user posted footage of what appeared to be officers closing in on the man.

He was taken to St. Barnabas hospital in stable condition. Police later said the gun was an "imitation pistol."

The NYPD's Force Investigation Division is looking into all three incidents.