A new television ad from congressional candidate David Calone tries to tie his Democratic primary opponent Anna Throne-Holst to Donald Trump, the presumptive GOP presidential nominee, escalating the fierce primary battle to face freshman Republican Rep. Lee Zeldin.

The ad criticizes three donations that Throne-Holst, a former Southampton Town supervisor, made to the Suffolk Conservative Party, which supports Trump. The commercial notes that Throne-Holst only became a Democratic Party member in 2015. Previously, she had belonged to the Independence Party.

The television ad starts with Throne-Holst saying, “I’ve been a Democrat for pretty much all of my life.”

The announcer says, “That’s not true. Anna became a Democrat just last year.”

“Anna gave money to the Conservative Party three times. Think about that. The Conservative Party supports Donald Trump. And Anna gave to them three times.”

“Anna Throne-Holst will say anything to get elected. How can Democrats trust her?”

In an interview, Throne-Holst called the ad a “low blow” and said Calone, a venture capitalist from Setauket, “has hit rock-bottom.”

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Throne-Holst said, “trying to link me to Trump is about as laughable and far-fetched as it gets. It’s the kind of campaigning we progressive Democrats frown on.”

Throne-Holst, a Sag Harbor resident who served as supervisor from 2010 to 2015, called on Calone to take the ad off the air and said she has attacked Trump as a racist and misogynist.

Calone spokesman Rahul Kale said, “The ad does not say Anna Throne-Holst supports Donald Trump at all. Really, this is about how she recently became a Democrat in November to run for the congressional seat.”

The Conservative Party contributions tie Throne-Holst to a “not-progressive agenda,” Kale said.

Throne-Holst spokesman Andrew Grunwald said Throne-Holst gave the contributions to attend Conservative Party fundraisers.

“As town supervisor, she attended tons of events throughout the community,” Grunwald said.

State campaign finance records show Throne-Holst gave $150 to the Suffolk Conservative Party Chairman’s Club three times in April 2011, $125 in December 2011 and $250 in May 2013.

Zeldin on Tuesday defended Donald Trump from charges that he’s racist for criticizing a federal judge because of his Mexican heritage by asserting that he could also argue that President Barack Obama “is a racist” because of his policies and rhetoric.

Zeldin (R-Shirley) made his comments — which Democrats quickly condemned — when he was pressed in a CNN interview to explain why he still backs Trump as the presumptive Republican presidential candidate while agreeing that Trump’s remarks about the judge are racist.