SINGAPORE - A video of a Hong Kong police officer pulling his gun on protesters after they surrounded him, taking his baton and beating him with it, has gone viral on Twitter.

The video, filmed by Wall Street Journal reporter Mike Bird and posted on his Twitter account early Wednesday (Aug 14) morning, has since garnered 4.3 million views and retweeted 15,900 times.

The officer was seen overwhelmed by rowdy protesters at the Hong Kong International Airport on Tuesday night, who then proceeded to take the officer's baton and assaulted him with it.

The group retreated only after the officer appeared to draw his gun from its holster in an attempt to fend them off.

In a statement, the Hong Kong government condemned the protesters' tactics, saying that their "violent acts" at the airport "are outrageous and have overstepped the bottom line of a civilised society."

Hong Kong police meanwhile said they have arrested five people during clashes with pro-democracy protesters at the airport Tuesday night, the Associated Press reported on Wednesday.

Assistant Commissioner of Police Operations Mak Chin Ho said the men, aged between 17 and 28, were arrested for illegal assembly.

Two were also charged with assaulting a police officer and possessing offensive weapons as riot police sought to clear the terminal.

Police officer had his baton taken from him and was attacked with it. Drew his pistol and aimed at protesters. Astonished nobody killed here tonight. pic.twitter.com/Wox8yziDnz — Mike Bird (@Birdyword) August 13, 2019

Mr Mak gave no further details, but said additional suspects were expected to be arrested, including those who assaulted the officer, the AP report said.

Hong Kong has been gripped by ten weeks of protests that have seen millions take to the streets, sparked by opposition to a planned law that would have allowed extraditions to mainland China.

The demonstrations have since evolved into a much broader campaign for democratic freedoms.