She told reporters: "The UK has no sovereignty, jurisdiction or right of supervision over Hong Kong".
Hundreds of other protesters who gathered at a police station in the tourist hotspot Tsim Sha Tsui were also dispersed by police with tear gas.
Fong, who was carrying 10 recently purchased laser pointers, none of which was equipped with a power supply, was later released without charge.
Riot police fire tear gas during the anti-extradition bill protest in Hong Kong, Sunday, Aug. 11, 2019.
After the report was published, the Chinese Foreign Ministry's commissioner for Hong Kong blasted the USA for the meeting and called on Washington "to immediately make a clean break from anti-China forces who stir up trouble in Hong Kong", "refrain from meddling with Hong Kong affairs, and avoid going further down the wrong path".
Demonstrators fanned out to different neighborhoods across the city, surrounding police stations, hurling projectiles at officers and disrupting traffic. News sources claimed that the United States publicly guided the strategy in the Hong Kong protests and said that Yi Zhuli instigated the activities.
As the protest movement has expanded, demonstrators have staged rallies across Hong Kong, attracting families, older people, civil servants and lawyers.
The current HKSAR government attaches great importance to the cultivation of young people, she said when addressing a graduation ceremony of the Hong Kong college students' military training camp.
Since protests started in June, sparked by a proposal to ease extraditions to the mainland, the idea has been mooted that business leaders wary of increased Chinese meddling in Hong Kong could move their money and operations to Singapore.
The protests checkered much of Hong Kong. This is the tenth consecutive weekend of pro-democracy demonstrations in Hong Kong.
At Tai Po, a residential area in the New Territories, protesters turned up for a planned march despite not receiving police approval.
The day before, China also rejected constant USA interference in Hksar affairs, especially in recent months, when agitation has taken over the island due to the explosion of violent protests against a bill to reform the extradition law.
By Sunday afternoon, over a thousand black-clad protesters peacefully swarmed the airport arrivals hall, chanting "Liberate Hong Kong, Revolution of our time". Police fired rounds of tear gas to disperse them.
"As Chinese, we were all saddened by recent acts of insulting the national emblem and flag", said the organizer of the gathering, who only gave his surname Lim.
"I don't think that leaking an American diplomat's private information, pictures, names of their children, I don't think that is a formal protest, that is what a thuggish regime would do", State Department spokeswoman Morgan Ortagus said. Earlier, they used batons to try to stop protesters. When asked by media about whether the People's Liberation Army (PLA)'s Hong Kong garrison would intervene in Hong Kong, nearly all officials in Beijing referred to the Basic Law provisions that regulate the duties and responsibilities of the garrison.