A sniper has shot dead a masked man who hijacked a commuter bus with 37 passengers and threatened to burn the vehicle.

In scenes reminiscent of the 90s movie Speed, the dramatic stand-off happened on a busy bridge in downtown Rio de Janeiro in Brazil.

Holding a gun and knife – and apparently armed with a lighter – the “very calm” hostage-taker doused the bus in gasoline and threatened to set it on fire.

Over the course of the four-hour stand-off, which started before dawn on Tuesday (local time), six of the 37 hostages were freed unharmed by the man who had identified himself as a police officer but made no demands.

The bus in which a gunman held 37 hostages. Photo: Getty

Rio’s elite police force, known as BOPE, took charge of negotiations with the hostage-taker and traffic was blocked in both directions on the bridge, with hundreds of vehicles waiting in line.

A sniper was positioned on top of a nearby fire truck for more than an hour,  waiting patiently for his moment which came when the hijacker eventually stepped outside of the bus.

TV footage shows the man throwing a backpack toward police and then falling to the ground as he tried to re-enter the vehicle – taken out by the police sniper.

Videos show the sniper celebrating after shooting the hijacker.

Brazil bus hijacker, armed with toy gun, shot dead by police https://t.co/Ob6b8R8Imd #GeneralNews #International https://t.co/9In7LCPM3y pic.twitter.com/7bEZSJbJ5p

— mySoulRebel dot com (@iamsoulrebel) August 20, 2019

As the hijacking ended, a visibly delighted state governor Wilson Witzel arrived by helicopter and bounded across the bridge to hug police and declare there had been no hostage casualties.

“I want to thank the police for its work,” Mr Witzel told TV Globo. He said this kind of situation “is happening in communities. They have rifles in the communities, terrorising the communities”.

The incident highlights the violent reality of daily life in Rio where citizens use Apps to avoid gun battles between police and drug gangs and vigilante militias.

The dramatic stand-off on a busy bridge lasted for four hours. Photo: Getty

About five people per day have died at the hands of police between January and June this year, putting it on track to be the highest number since records started being kept in 2003.

The bridge where the hostages were seized links Sao Goncalo, an area struggling with poverty and violence, with Rio and many people use it to go to and from work.

The safe release of hostages was considered a victory for the governor, who has come under growing pressure in recent weeks over the number of people slain by cops, media report.

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Governor Witzel, who says police should kill anyone with a rifle and has ordered snipers to fire on suspects from helicopters, celebrated the outcome but lamented the death of the hijacker.

“We don’t want anyone to die, but … the police will act rigorously and will not be lenient with those who endanger other people’s lives,” he said.

“Some people do not always understand that police work sometimes has to be this way,” he said.

“If they had not shot this criminal, many lives would not have been spared.”

Brazil’s President Jair Bolsonaro tweeted his congratulations to police.

“The criminal was neutralised and no hostage was injured. Today, no family member of an innocent person will be in tears.”

-with AAP