The US on Thursday branded China a "thuggish regime," hours after Beijing issued a stern warning to American diplomats in Hong Kong to not interfere in the city's internal affairs.
The US' reaction came after local media reports emerged that a US official from the American consulate general in Hong Kong had met with a local "independence group".
A newspaper based in Hong Kong had reportedly published a photograph of the American diplomat meeting with protesters of the city's pro-democracy movement.
Following this, the Chinese Foreign Ministry on Thursday expressed displeasure over the reports and lodged a protest over the US diplomat meeting with the demonstrators.
Responding to the same, State Department spokesperson Morgan Ortagus said: "I don't think that leaking an American diplomat's private information, pictures and names of their children is a formal protest. That is what a thuggish regime would do. That is not how a responsible nation would behave. This is unacceptable."
Ortagus said that US diplomats meet with government officials in countries where there is an American embassy established as per normal diplomatic practices.
"This is what American diplomats do every single day around the world. American diplomats meet with formal government officials...not just in Hong Kong or China. This literally happens in every single country in which an American embassy is present. So, our diplomat was doing her job and we commend her for her work," the spokesperson said.
Since June, Hong Kong has seen nine consecutive weeks of anti-government protests that began against a now-suspended extradition bill, which have since broadened to include calls for democracy and police accountability.
Multiple protests sometimes violent continue to take place in the semi-autonomous state despite the city's pro-Beijing leader Carrie Lam publicly apologising for proposing the controversial legislation and announcing later that the bill was "dead".
Protesters have also demanded the release of their fellow agitators arrested during the mass demonstrations, a call turned down by Lam earlier this month saying it was not "within her power".
( With inputs from ANI )