Wary residents and curious tourists stop to take photos, while inside the elegant Union Station a string trio plays "What a Wonderful World."

Christian Calhoun, a 26-year-old consultant who was born and raised in the US capital, told AFP that seeing the troops made him "more than disappointed -- I'm furious."

"It's a lot of standing around," he added.

Declaring that Washington is overrun by crime and plagued by homeless people, President Donald Trump has deployed 800 National Guard troops, as well as ordering a federal takeover of the city's police department.

Over more than an hour on Thursday afternoon, the most that the handful of troops at Union Station interacted with the public was to let a French tourist take a selfie with them.

Larry Janezich, an 81-year-old resident, said he had not seen the troops taking part in "any kind of meaningful action that is dedicated to the prevention of crime."

Patricia Darby, a 65-year-old retiree, said that the troops "don't want to be here," pointing to how some had their faces covered.

Calhoun said he does "feel bad" for them as they wore heavy combat gear as temperatures soared above 90 degrees Fahrenheit (33 Celsius).

- 'Fake news' -

On his Truth Social platform, Trump this week described Washington as "under siege from thugs and killers," with higher crime rates than "many of the most violent Third World Countries."

Residents outside Union Station rejected the apocalyptic image.

"It's ridiculous, and it really just shows how (Trump) sees the people that live here," Calhoun said.

"It's totally false, and obviously promulgated on his media to justify an unwarranted exercise of federal power," Janezich said.

Gerry Cosgrove, a 62-year-old tourist from the Scottish city of Edinburgh only in Washington for two days, had a simple response when asked about Trump's portrayal of the city: "To quote a phrase: fake news."

Trump has also ordered homeless people to "move out" of Washington.

"Where are they going to go?" Darby asked, after fetching a bottle of water for a homeless person in the heat.

Randy Kindle, who volunteers with a protest group in a tent outside Union Station, told AFP he was afraid that homeless people could now end up in confinement or jail "when all they need is help."

Guadalupe, a homeless man in his late 70s originally from Mexico, told AFP that the troops had asked him to move on Wednesday night.

"They have no manners," he said in Spanish.

"I almost felt sick" during the interaction, he added.

Calhoun said he had mostly seen the troops outside train stations, adding that he noticed they had "a lot of focus on cannabis use."

Washington legalized cannabis use on private property in 2015, however it is still prohibited under federal law.

Several residents also raised the cost of deploying the troops in their city.

"It's a waste of money -- I think DC was safe," Darby said.