Chinese nationalists have rallied in central Hong Kong in support of besieged police officers and accused the US Central Intelligence Agency (CIA) of whipping up anti-Government sentiment in the former British colony.

Key points: Pro-Beijing protesters demonstrated outside of Hong Kong's police headquarters on Tuesday

Pro-Beijing protesters demonstrated outside of Hong Kong's police headquarters on Tuesday They claim that the city's anti-Government protesters have had help from the US's CIA

They claim that the city's anti-Government protesters have had help from the US's CIA Hong Kong Chief Executive Carrie Lam is visiting the mainland for meetings this week

Hundreds of activists waving flags gathered at Hong Kong's police headquarters late on Tuesday in a demonstration to counter the democracy movement that has taken hold in the Chinese territory.

For five months pro-democracy activists have faced off with authorities during increasingly violent street demonstrations to oppose what they fear is Beijing's attempts to curb freedoms in the Asian financial hub.

Hundreds of pro-Beijing activists gathered at the offices of the Hong Kong police to show their support for the city's officers. ( ABC News: Adam Kennedy )

Many of the pro-Beijing supporters who gathered in support of Hong Kong's Government and police told the ABC they believed US intelligence agencies were largely responsible for the city's recent unrest.

"Americans give Hong Kong, some of the people here, a lot of support — like the CIA," says Jimmy Wong, a Hong Kong-born man who attended the rally.

A similar view was expressed by Angelo Giuliano, a European citizen who has lived on the Chinese mainland for 25 years, but regularly visits Hong Kong.

"The CIA are here in Hong Kong and I believe there's probably a few hundred agents," Mr Giuliano told the ABC after attending the rally.

Chinese resident Angelo Giuliano claimed that the CIA had "a few hundred agents" in Hong Kong. ( ABC News: Adam Kennedy )

Some of the nationalists who attended the rally carried slogans depicting pro-democracy protestors as "cockroaches", while urging Hong Kong's embattled leader Carrie Lam to take a harder line against them.

"I hope she can change the law or something like that to stop people doing any more damage on the streets," Mr Wong said.

This week Hong Kong's Chief Executive Carrie Lam has flown to the Chinese mainland for meetings with the Chinese Government.

On Tuesday, Beijing's official news agency Xinhua reported that Chinese President Xi Jinping had demanded "unswerving efforts" to end the violence in the Hong Kong and punish those responsible "to safeguard the well-being of the general public."