A Hong Kong protester has been shot by a police live round, with the incident streamed live on Facebook, as demonstrators disrupted the Monday morning commute leading to chaotic scenes across the city.

Video of the incident showed a police officer grappling with a protester dressed in white at a zebra crossing. As other protesters approach, the officer pulls out his service-issue revolver and fires at the abdomen of a man dressed in black.

Elsewhere in the city, a man was set on fire as two groups appeared to argue over national identity, and there have been widespread reports of teargas firing across Hong Kong – unusual scenes during daylight hours in the working week.

At a hastily called news conference, the city’s chief executive Carrie Lam described both the police shooting and the incident with the man on fire as “very worrying”. The latter, which appeared to involve a masked protester throwing flammable liquid on an older man who had said the demonstrators were “not Chinese”, she called an “inhumane act”.

Ms Lam described the protesters as “enemies of the people”, saying they “will never win” – comments which may signal a hardening stance from the government.

Asked about the police shooting, she rejected calls to set up an independent inquiry into allegations of excessive force, saying that this would mean giving in to one of the protest movement’s demands.

“If there’s still any wishful thinking that by escalating violence the Hong Kong government will yield to pressure to satisfy the so-called political demands, I’m making this statement clear and loud here: that will not happen,” Ms Lam said.

“Violence is not going to give us any solution to the problems that Hong Kong is facing. Our joint priority now, as a city, is to end the violence and to return Hong Kong to normal as soon as possible.”

Video of the Sai Wan Ho district shooting show the police officer firing multiple rounds before he and a colleague pinned down two protesters, including the one who was wounded.

Police said only one of the protesters was hit, and that he was undergoing surgery. Later in the day hospital sources were quoted as saying he was resting and not at “immediate risk of death”, having previously been described as “critical”.

According to the South China Morning Post, police told reporters at a briefing that the protesters were trying to take the officer’s gun, so he attempted to fire warning shots but inadvertently hit one of the protesters.

But Amnesty International issued a statement calling the shooting a “shocking low for the Hong Kong police” and “clear evidence of a reckless use of force”.

They cited another incident on Monday in which a police officer had been filmed apparently driving his motorbike at high speed into a group of protesters. Police said the officer had been immediately suspended pending an investigation of the “very serious” case.

“These are not policing measures – these are officers out of control with a mindset of retaliation,” said Man-Kei Tam, director of Amnesty International Hong Kong.

“This pervasive, heavy-handed behaviour shows the police cannot investigate themselves. Today’s actions again require an urgent independent investigation. The authorities must review their approach to help de-escalate the situation and prevent more lives being put at risk.”

It is the third time a protester has been shot by the police since the demonstrations began in June with anger at an unpopular extradition bill and the perceived encroachment of Hong Kong’s freedoms by Beijing.

Each incident has sparked outrage and allegations of excessive use of force, first on 1 October when an 18-year-old student was shot in the chest in an incident that was also caught on video, and then when a 14-year-old boy was shot in the leg on 4 October.

A video grab shows the moment a police officer shoots a black-clad pro-democracy protester in the abdomen during a protest in Sai Wan Ho district, in Hong Kong, on Monday morning (Cupid News/AFP/Getty) (Cupid News/AFP)

Tensions are already enflamed after a weekend in which six pro-democracy politicians were arrested on charges of obstructing the local assembly, relating to a raucous 11 May meeting over the extradition bill.

All were freed on bail, but the decision to arrest them now was seen as a sign of patience wearing thin among Ms Lam and her Beijing-backed devolved administration.

On Friday, the city saw its first confirmed death directly related to the at-times violent street demonstrations, as a protester who fell during clashes with police last Monday finally succumbed to his injuries in hospital.

The morning protests this Monday saw thousands attempt to block major roads and MTR metro routes, at times throwing heavy objects onto the streets below.

The rail operator was forced to suspend several lines, and public broadcaster RTHK reported that a fire had been started inside a train at Kwai Fong station.

The number of high-profile violent incidents has increased as Hong Kong prepares to conduct district elections on 24 November, with pro-Beijing parties expected to take a hit at the ballot box.

Hong Kong protesters out in force after months of turmoil: In pictures Show all 32 1 /32 Hong Kong protesters out in force after months of turmoil: In pictures Hong Kong protesters out in force after months of turmoil: In pictures A protester throws a stone into a building at Hong Kong Polytechnic University on 11 November Reuters Hong Kong protesters out in force after months of turmoil: In pictures Police patrol the streets of Hong Kong the day after an officer shot a protester during a protest on 11 November EPA Hong Kong protesters out in force after months of turmoil: In pictures Riot police stand guard during a protest against police brutality in Hong Kong on 27 October EPA Hong Kong protesters out in force after months of turmoil: In pictures Protesters carry traffic cones to build a barricade during anti-government protests in Causeway Bay, Hong Kong on 11 November Reuters Hong Kong protesters out in force after months of turmoil: In pictures Protesters use obstacles and bricks to block a road in Hong Kong on 11 November AP Hong Kong protesters out in force after months of turmoil: In pictures Graffiti on a window smashed by student protesters in Hong Kong Polytechnic University AP Hong Kong protesters out in force after months of turmoil: In pictures Protesters carry US and British flags during a demonstration in Hong Kong on 11 November Reuters Hong Kong protesters out in force after months of turmoil: In pictures A protester throws a bottle of water as he is shrouded in tear gas during a demonstration in the Tsim Sha Tsui district of Hong Kong on 27 October Reuters Hong Kong protesters out in force after months of turmoil: In pictures Journalists take pictures of police officers as they move to disperse protesters in Hong Kong on 27 October Reuters Hong Kong protesters out in force after months of turmoil: In pictures An man lies injured after being attacked by protesters who suspected him of being an undercover police officer on 27 October EPA Hong Kong protesters out in force after months of turmoil: In pictures A man runs among tear gas during a protest in Hong Kong on 27 October Reuters Hong Kong protesters out in force after months of turmoil: In pictures Protesters gather on a field in the Tsim Sha Tsui district of Hong Kong on 27 October Reuters Hong Kong protesters out in force after months of turmoil: In pictures Pro-democracy protesters turn away from a fire lit outside the Causeway Bay Mass Rapid Transit (MTR) station in Hong Kong on 4 October Getty Hong Kong protesters out in force after months of turmoil: In pictures People rest near rows of riot police officers during a protest in Mong Kok, Hong Kong on 27 October Reuters Hong Kong protesters out in force after months of turmoil: In pictures Pro-democracy protesters hold umbrellas as police fire tear gas at them ouside Tai Koo MTR station in Hong Kong on 3 October Getty Hong Kong protesters out in force after months of turmoil: In pictures Hong Kong police fire a water cannon from the central government office at protesters during a mass rally on the 70th anniversary of the founding of communist China on October 1 AFP/Getty Hong Kong protesters out in force after months of turmoil: In pictures Protesters burn a Chinese national flag during a mass rally on the 70th anniversary of the founding of communist China on 1 October AFP/Getty Hong Kong protesters out in force after months of turmoil: In pictures Protesters remove signs celebrating the 70th anniversary of the founding of communist China during a mass rally in Hong Kong on 1 October AFP/Getty Hong Kong protesters out in force after months of turmoil: In pictures Cardboard boxes set alight by protesters burn in the streets of Hong Kong during a mass rally on the 70th anniversary of the founding of communist China on 1 October EPA Hong Kong protesters out in force after months of turmoil: In pictures An anti-China banner has been placed in a barricade during a mass rally on the 70th anniversary of the founding of communist China on 1 October EPA Hong Kong protesters out in force after months of turmoil: In pictures A pro-democracy protester runs away after police fire a tear gas canister in Hong Kong's Wong Tai Sin district on October 4 Reuters Hong Kong protesters out in force after months of turmoil: In pictures Protesters run after police fire tear gas during a mass rally on the 70th anniversary of the founding of communist China on 4 October AFP/Getty Hong Kong protesters out in force after months of turmoil: In pictures Pro-democracy protester take cover after police fire a tear gas canister in Hong Kong's Wong Tai Sin district on 4 October Reuters Hong Kong protesters out in force after months of turmoil: In pictures The rally comes after months of protests on the streets of Hong Kong which began in oppposition to a proposed extradition bill EPA Hong Kong protesters out in force after months of turmoil: In pictures The extradition bill would have allowed the government to extradite people to China if they were facing certain criminal charges AFP/Getty Hong Kong protesters out in force after months of turmoil: In pictures Opposition to the bill stems from the fear that the Chinese government would abuse this power for political or commercial reasons EPA Hong Kong protesters out in force after months of turmoil: In pictures Protesters soon came to demand greater freedom and universal suffrage under the One Country, Two Systems principle AFP/Getty Hong Kong protesters out in force after months of turmoil: In pictures Protesters are wearing black to symbolise opposition to China as they take to the streets in a "day of grief" while the Chinese state celebrates the 70th anniversary of its communist founding AFP/Getty Hong Kong protesters out in force after months of turmoil: In pictures A protester charges forward holding umbrellas as a mass rally breaks out in violence in Hong Kong on 1 October AFP/Getty Hong Kong protesters out in force after months of turmoil: In pictures A protester pours water on a tear gas canister fired by police during a mass rally on the 70th anniversary of the founding of communist China on 1 October Reuters Hong Kong protesters out in force after months of turmoil: In pictures A protester carries a vandalised Chinese flag through Hong Kong during a mass rally on the 70th anniversary of the founding of communist China on 1 October EPA Hong Kong protesters out in force after months of turmoil: In pictures Protesters carry a banner that denounces the celebration of the 70th anniversary of the founding of communist China on 1 October EPA

Opposition MPs have accused the government of deliberately trying to provoke violence in order to justify cancelling or postponing the elections.

In a news release regarding the Sai Wan Ho district shooting incident, the Hong Kong government said police had been responding to vandalism and disruptions to traffic.

“During police operations, one police officer has discharged his service revolver, one male was shot,” the release said, adding that officers also drew their guns in the Shatin and Tung Chung neighbourhoods.