WASHINGTON — Rep. Claudia Tenney’s campaign in upstate New York is warning staffers their safety is at risk because the family of her Democratic opponent, Anthony Brindisi, is “criminal” and “thuggish.”

The campaign cautioned staffers in a memo to “not go out at night alone,” “be aware of strange cars,” “be alert to whether you are being followed” and “examine your locks” for tampering.

The memo, obtained by The Post, says the precautions are necessary because of the criminal history of Brindisi’s father and brother.

“Brindisi’s family has used their political connections to get away with violence, intimidation and thuggish behavior for years. As the Brindisi family watches Anthony’s political career end, they may return to what they know—violence and intimidation,” the memo said.

Tenney is locked in one of the toughest congressional races in the country as Democrats seek to flip the House in November.

Her district covers central New York, including the cities of Utica and Binghamton.

Tenney made similar claims about Brindisi’s family background last year.

But in an interview with The Post, she said she has a “good relationship” with her opponent and doesn’t blame him or his family — before trashing the family.

“As far I know, it has nothing to do with the Brindisi family,” Tenney said.

“This is rural upstate New York, which is usually kind of a quiet place,” Tenney said. “But I have 11 colleges in my district and that’s where most of these people are coming from,” she added, speaking of the troublemakers.

The memo outlines purported mob ties of Brindisi’s father, Louis, a one-time lawyer for organized crime figures who pleaded guilty to possession of cocaine in 1991 but insists he’s not a mobster or a drug dealer.

“Look at what the father has been charged with and somehow has been able to get out of … I’ve never even had a speeding ticket,” Tenney told The Post.

“His brother [Andrew] three years ago was charged with running over a guy ….It was caught on a camera and many police have said this should have been attempted murder. It was not. And he kept his job in the city of Utica and his father gave big donations to the city’s mayor. … Can you imagine if someone in my family ran over somebody?”

Records show Andrew Brindisi was sentenced to one year probation for leaving the scene of an accident in 2014.

Tenney claimed the threats include a “black Jeep” regularly parked outside her home, Facebook death threats, vandalized campaign signs and slashed tires of her staff.

Ellen Foster, the campaign manager for Brindisi, a state assemblyman, issued a statement accusing Tenney of a cheap smear.

“These kinds of blatant and false attacks on Italians are nothing new for Claudia Tenney. In fact, this toxic rhetoric is a main reason nothing gets done in Washington, and shows exactly why she needs to be replaced. It’s clear that she’s pushing stereotypes and fear to distract from her record of giving billions in tax breaks to her special interest donors and voting to cut Medicare while blowing a hole in our national debt. That’s the real threat upstate New Yorkers are facing,” the statement said.

And Jim Testani, former president of the Binghamton Sons of Italy and former Broome County Democratic Committee chairman, said Tenney’s allegations have “no basis in reality. I know Anthony Brindisi. He’s an upstanding member of the Assembly, a committed father and husband, and is running an honorable campaign.”