US Republican presidential nominee Donald Trump worked the fry station at a Pennsylvania McDonald’s on Sunday, drawing attention to his claims that Democratic nominee Kamala Harris lied about previously working in the fast-food industry.

As reporters and aides watched, an employee showed the former president how to dunk baskets of fries in oil, salt them, and put them into boxes using a scoop.

“It requires great expertise, actually, to do it right and to do it fast,” Trump said with a grin, putting away his suit jacket and wearing an apron over his shirt and tie.

The visit came as he tried to counter Democratic nominee Kamala Harris’s accounts on the campaign of working at a McDonald’s while at university, an experience that Trump has claimed — without offering evidence — never happened.

A large crowd lined the street outside the restaurant in Feasterville-Trevose, a place part of akey swing voter area in Pennsylvania.

The McDonald’s itself was shut off to the public during Trump’s visit, a fact which caused some controversy online. Images circulated Sunday night of a paper stuck to the restaurant’s door saying it would be closed until 4 pm local time to “accommodate a visit at the request of former President Trump and his campaign.”

After serving bags of takeout to people in the drive-thru lane, Trump leaned out of the window, still wearing the apron, to take questions from the media staged outside.

He joked about getting one reporter ice cream and when another asked what message he had for Harris on her 60th birthday on Sunday, Trump said, “I would say, ‘Happy Birthday, Kamala,’” adding, “I think I’ll get her some flowers.”

Trump did not directly answer the question of whether he might support increased minimum wages after seeing McDonald’s employees in action, but he said, “These people work hard. They’re great.”

Trump claims Harris ‘lied about working’ at McDonald’s

Trump has fixated in recent weeks on the summer job Harris said she held while at university, working the cash register and making fries at McDonald’s. Trump says the vice president has “lied about working” there but has not offered evidence.

Representatives for McDonald’s did not respond to a message about whether the company had employment records for one of its restaurants 40 years ago.

However, in an interview last month on MSNBC, the vice president pushed back on Trump’s claims, saying she worked at the fast-food chain four decades ago when she was in university.

“Part of the reason I even talk about having worked at McDonald’s is because there are people who work at McDonald’s in our country who are trying to raise a family,” she said. “I worked there as a student.”

Trump has long spread groundless claims about his opponents based on their personal history, particularly women and racial minorities.

Before he ran for president, Trump was a leading voice of the “birther” conspiracy that baselessly claimed President Barack Obama was not an American citizen and therefore was ineligible to be president.

During his first run for president, Trump also repeated a tabloid’s claims that Texas Senator Ted Cruz’s father, who was born in Cuba, had links to President John F Kennedy’s assassin, Lee Harvey Oswald.

Trump even said during his presidential debate with Harris that Haitian immigrants who had settled in Ohio were eating residents’ pets — a claim he suggested in an interview on Saturday was still true even though he could provide no confirmation.

Why this McDonald’s?

“It is a fundamental value of my organisation that we proudly open our doors to everyone who visits the Feasterville community,” the McDonald’s location’s owner, Derek Giacomantonio, said in a statement.

“That’s why I accepted former President Trump’s request to observe the transformative working experience that 1 in 8 Americans have had: a job at McDonald’s.”

Trump is especially partial to McDonald’s Big Macs and Filet-o-Fish sandwiches. He’s talked often about how he trusts big chains more than smaller restaurants since they have big reputations to maintain, and the former president’s staff often pick up McDonald’s and serve it on his plane.

Jim Worthington, a Trump supporter and fundraiser who owns a nearby athletic complex and chaired Pennsylvania’s delegation to the Republican National Convention, said he arranged Trump’s visit to the locally owned McDonald’s franchise.

The campaign contacted him about looking for a McDonald’s in Pennsylvania, and Worthington started searching. He got in touch with Giacomantonio through a friend and talked the franchise owner through some initial nervousness.

Giacomantonio needed to know that McDonald’s corporate offices would be OK with it, first. Second, he was concerned that being seen as a Trump supporter would hurt his business or a spark boycott, Worthington said.

“He certainly had concerns, but I eased his mind, and talked to him about the benefits,” Worthington said.