Hillary Clinton supporters are fuming that Gov. Cuomo spent several minutes chatting amiably with Donald Trump at Sunday’s 9/11 ceremony at Ground Zero.

Democrats who attended the solemn event — the 15th anniversary of the World Trade Center terror attacks — said Cuomo’s chumminess with the GOP presidential nominee was too much to watch.

“People are saying, ‘Do you believe the governor did that?’ ” said one prominent New York Democrat. “People are really chirping about this. Hillary’s people were taken aback. It’s Cuomo being too clever by half.”

Petty partisan political carping has always been off limits on the 9/11 anniversary.

In fact, during the 2008 presidential race, rival candidates Barack Obama and John McCain walked down a ramp together to the memorial site in a show of national unity and threw flowers into a reflecting pool.

The private griping about the Cuomo-Trump chat demonstrates this year’s nasty White House race has even infected America’s most solemn civic event.

Clinton, who was a New York senator on 9/11, nearly collapsed while leaving Sunday’s ceremony.

Cuomo worked as housing secretary for former President Bill Clinton and chairs Hillary Clinton’s New York Leadership Council.

‘We were actually talking to each other for a long while… We get along very well.’ - Donald Trump

Trump confirmed on Thursday that he had a “long talk” with the governor at the ceremony.

“We were down there talking to each other. We had a long talk. We were actually talking to each other for a long while,” Trump said on Post columnist Fredric U. Dicker’s Talk 1300AM Albany radio show. “We get along very well.”

Asked what he and Cuomo discussed, Trump said, “Just the weather. We were talking about how nice and cool it was. It was actually a beautiful day.”

After a video showed Clinton’s knees buckling and her nearly fainting while leaving the ceremony, a campaign spokesman initially said she “overheated.”

The campaign later said Clinton had been diagnosed with pneumonia two days earlier.

Former Mayor Rudy Giuliani, a Trump adviser, defended Cuomo.

“It looked pretty darn friendly,” Giuliani said. “But that’s what happens at that ceremony. Everyone is nice to each other because it’s a solemn event.”

Giuliani said former Mayor Mike Bloomberg and Trump shook hands, even though Bloomberg trashed Trump and endorsed Clinton at the Democratic national convention.

The Trump and Cuomo relationship goes back decades.

Cuomo’s dad, former Gov. Mario Cuomo, had worked with Trump’s father, Fred Trump, as a private lawyer.

And while Mario was governor, Andrew, through his law firm, counted the Trump Organization as a client.

Asked for comment, Cuomo spokesman John Kelly said, “The September 11th Memorial Event is not a time for politics. The governor welcomes all well-wishers to New York to remember this solemn occasion.”