Mayor Eric Adams grimaced as he stood next to a grinning Veep Kamala Harris at Manhattan’s 9/11 memorial Monday — a scene that said it all about tensions between local and federal Dems over migrants.

Harris, who was filling in for President Biden at the hallowed service, spent much of her time in the morning before the ceremony smiling and laughing — with Gov. Kathy Hochul, who was on the other side of her, videos show.

Adams, standing on the vice president’s other side, frowned as he looked away — an apparently frosty encounter putting on public display the current wedge between City Hall and the White House over the crisis.

Hizzoner insisted to The Post while walking back to his office after Monday’s Lower Manhattan service that he and Harris exchanged pleasantries — but that he did not bring up the flood of migrants overwhelming the city.

“I wanted to be there to show my respect,” the mayor said, referring to the service.

He added that he is open to discuss with the Biden administration the country’s border disaster “if there’s an opportunity, not a Ground Zero, to engage in the things that have to be talked about.”

Rhetoric between the two typically friendly sides has intensified over recent weeks as the city struggles to house, feed and educate the thousands of migrants arriving in the Big Apple each week.

Adams has staunchly and repeatedly urged Biden to push for more control at the border and provide a significant increase in funding to help cover the estimated roughly $12 billion it will cost the city through 2025.

He also has ripped the Hochul administration for not doing enough to help handle the influx of asylum seekers.

On Sunday, Adams doubled down on his controversial claim that the migrant crisis will “destroy” the Big Apple if it doesn’t get more aid.

“I have to be honest with New Yorkers with what we’re about to experience — a financial tsunami that I don’t think this city has ever experienced,” Adams told PIX 11’s “PIX on Politics” over the weekend.

“This is not utopia,” Adams said. “New York City cannot manage 10,000 people a month with no end in sight. That can’t happen, and that is going to undermine this entire city.”

The mayor had issued a grim warning a day earlier saying that without more aid from the Biden administration, city agencies would have to be cut by up to 15% over the next year.

“We’re going to show New Yorkers exactly what we’re faced with because transparency is crucial here. I have to be honest to New Yorkers what we are up against,” Adams said.

“We’re talking $12 billion, $12 billion of running our city: sanitation, police, education, libraries, everything that we have to run the city,” he said. “There’s a minimum amount of money that comes in that we have to address this crisis as a national crisis, and we’ve been ignored.”

More than 110,000 asylum seekers have come to New York City from the southern border since spring 2022, with nearly 60,000 of them currently in the city’s care.

Yet so far, the Biden administration has provided a mere $145 million in federal funds.