A 9/11 victim’s parents were left shocked and appalled as they watched Wednesday’s memorial at Ground Zero and saw a teenage girl they didn’t know launch into a political rant about Syria while reading their son’s name.

Brittney Cofresi, 15, declared, “President Obama, please do not bring us to another war,” after saying the name of her “uncle,” Sept. 11 victim Sal Papasso Jr., who was only a distant relative of the Brooklyn girl.

She later went on Twitter to brag that her hijacking of the service had made her a viral star.

“I’m famous guys honestly go look up 15-year-old girl asks Obama not to go to war while speaking at the 9/11 memorial,” she tweeted.

Papasso’s family is estranged from Cofresi’s aunt — and they didn’t recognize her as she exploited their son for her stunt.

“My mother saw her reading Sal’s name and said, ‘Who is that? She had no idea who she is,” Sal Jr.’s brother, Tom Papasso, told The Post. “We were all stunned. It was completely inappropriate to use this day for that. It was not the time nor the place for a political statement.”

Cofresi was a toddler when Papasso, a state tax-fraud investigator, died at in the South Tower of the World Trade Center at age 34.

She is related to him though marriage. Her aunt, Christine, is Papasso’s widow. Christine and Papasso’s blood relatives have been estranged for more than a decade.

“I was only 3 when you were taken from us, and we love and miss you very much,” Cofresi said of Papasso as she began speaking at the service. She then launched into her anti-war harangue.

“Why is [Christine’s] sister’s daughter reading Sal’s name and then following it with a statement about war?” Tom Papasso fumed.

As she spoke, Cofresi held up a picture of herself as a toddler with Papasso playing together in a ball pit at a birthday party.

She later told The Post that she goes to the event every year, but this year, she was moved to speak out about the prospect of bombing Syria after seeing President Obama’s TV speech Tuesday.

She said she was “nervous” as she spoke, but she’s glad she did it.

“I don’t have any regrets saying it, because I feel my opinion is important,” Cofresi said. “I think it took a lot of courage.”

Cofresi’s mother, Karen, said Sal’s family is “entitled to their opinion,” but she stands behind her daughter.

“I’m proud of her,” Karen said. “She has class and intelligence. She said a message to the president and said ‘please.’ She didn’t say, ‘Go Giants!’ ”