An off-duty cop punched a 71-year-old woman in the face during an argument over her dog in Brooklyn, according to police sources and the lady.

NYPD Officer Vladimir Radionov, 46, allegedly became enraged when Janet Goldschmidt tried to bring her 9-pound Yorkshire terrier onto the elevator of their building on Sea Coast Terrace in Brighton Beach and began arguing with her around 7:30 a.m. Sunday.

“I think if I didn’t run away, he would kill me,” Goldschmidt told The Post on Monday, the day after Officer Vladimir Radionov, 46, was charged with second-degree assault for the alleged attack. “He was so angry.”

“He came at me like a bull,” Goldschmidt told The Post. “He just attacked me.”

She said she’d just returned from walking her small dog, whose name is Alvick, when Radionov started cursing her after she stepped into the elevator.

“He says, ‘Take your motherf–king dog out of the elevator. I don’t want to go up with your f–king dirty dog,'” she recalled.

Pets are only allowed in the service elevator, but Goldschmidt asked if she could ride up to her floor in the passenger lift first.

“He said ‘No’ and started punching me,” she recalled. “I throw a cup of coffee, thinking this is going to stop him but it doesn’t. He punches me in the back. He grabs me and pulls me out like I am a child.”

Video shows Radionov dragging her out of the elevator, then pushing her when she tries to get back in, sources said.

At one point, the elderly woman fell backward to the floor, injuring her tailbone and hitting the back of her head. She also scraped her arm during the fall, sources said.

When Radionov tried to get back into the elevator, Goldschmidt lunged after him to try to retaliate, sources said.

He then allegedly gave her one last shove before she hurled a cup of coffee on him as the doors shut.

“I am so surprised. He is a police officer,’’ Goldschmidt said. “Police officers are supposed to keep us safe. Instead, he was acting like a criminal.’’

Goldschmidt called the building superintendent and described her attacker before he gave her Radionov’s name and apartment number.

She then called cops, who went up to Radionov’s apartment and brought him down on the elevator.

Once in the lobby, Goldschmidt identified Radionov to cops, who arrested him and later charged him with assault.

She was taken to Coney Island Hospital for treatment.

“He hit a 71-year-old woman, it is unbelievable,” Goldschmidt said. “I thought I was going to die from anxiety, I couldn’t breathe.”

Radionov was freed on $5,000 bail, although an order of protection was issued against him, meaning he isn’t allowed to return to his building.

Radionov’s wife insisted he would never punch anyone. “He is not violent,” Angelina Radionov said.

Additional reporting by Danika Fears and Emily Saul