The State Department confirmed that its diplomat met with activists, but said that US diplomats regularly meet with government officials, opposition figures, business leaders and more. Protesters say police were slow to protect them.
Local pro-Beijing newspaper Ta Kung Pao published a photograph of the diplomat, identifying her as Julie Eadeh.
It came on the same day a state department spokeswoman denounced China as a "thuggish regime" after a state newspaper published the name and photo of a USA diplomat allegedly talking to activists. "This is what other countries' diplomats do", she said.
"I don't think that leaking an American diplomat's private information - pictures, names of their children - I don't think that that's a formal protest, that is what a thuggish regime would do", Morgan Ortagus said at a State Department briefing on Thursday.
To help deal with the protests, Hong Kong has recalled from retirement a police commander who oversaw the response to pro-democracy demonstrations in 2014. The statement said the government and the travel industry were working to minimize disruptions and "all stand ready to welcome and assist visitors to Hong Kong any time".
"We again sternly urge the USA side to abide by worldwide law and norms governing global relations and stop its wrong actions of interfering in other countries' domestic affairs and undermining their sovereignty and security".
That shop in Hong Kong was later vandalised, according to Taiwanese broadcaster TVBS.
Wong said the meeting was nothing out of the ordinary.
"We want to tell the passengers what's happening in Hong Kong, so we prepared these leaflets showing our five major demands", said Charlotte Au, a 16-year-old student among the protesters.
Police have fired tear gas, rubber bullets and other projectiles at protesters, with demonstrators responding with metal sticks, bricks, gasoline bombs and carts full of burning debris.
The requests include the permanent withdrawal of the extradition bill; an end to the government's characterisation of some protests as "riots"; the release of all arrested protesters without charges; an independent investigation into police violence; and the relaunch of the city's electoral reform.
An email attributed to a Hong Kong government spokesman conceded recent road blockages and confrontations between police and protesters had caused inconveniences, but said they were confined to limited areas.
The groups added that police, in many instances, could have avoided using such aggressive weapons and opted for some less-threatening options.
Signs held by protesters in the arrival hall included ones saying "There are no rioters, only tyranny", while pamphlets stacked in piles warned visitors of the heavy use of tear gas by police. So far, it has generated more than 110,500 signatures.
Hong Kong is a former British colony that is now part of China but enjoys autonomy thanks to the "one country, two systems" approach.
"[Hong Kong] is a political nuclear bomb", Fong told the Hong Kong bureau of The Epoch Times on August 8.
Zhang said bowing to protesters' demands would not resolve the crisis. One protester held up a sign that read "Sorry for the inconvenience we are fighting for the future of our home".