
This is the moment a flash-bang grenade appears to go off amid a Patriot Prayer march in Portland, seconds before a melee between the right-wing group and Antifa.

Four people were arrested amid the violence on Saturday, which broke out when the pro-Trump group's scheduled march encountered an opposing group associated with a second nearby rally.

Neither rally was directly related to President Donald Trump's immigration policy, which drew peaceful protests elsewhere in Portland and across the country on Saturday.

Police said four people were transported to area hospitals by ambulance, three with non serious injuries and one with a serious but non-life threatening injury. One police officer also suffered what was believed to be a non-serious and non-life-threatening injury as a result of being struck by a projectile.

Patriot Prayer (background) had a permit to march on Saturday in Portland when it encountered Antifa (foreground)

A flash-bang grenade appears to go off in the midst of the right-wing group, which says the march was for free speech

Right-wing marchers clashed with Antifa in the street shortly before the police revoked Patriot Prayer's permit

'They were throwing rocks, they were throwing bottles, you need to tell the truth,' one middle-aged woman in a Make America Great Again hat said after the clashes, addressing media in remarks caught on camera.

'No one on our side did anything violent, everything was self defense,' she claimed. 'You guys have to stop it because you're encouraging these people to come down here and try to murder us.'

Organizers of the Patriot Prayer rally said it was to protest the lack of police protection from left-wing groups at prior events in Portland.

'The nation is EXTREMELY angry about how Portland citizens treated Freedom Loving Americans who marched in the streets of this dangerous city,' the group said in an invitation to the event.

Antifa groups called Patriot Prayer a fascist and racist group. Patriot Prayer leaders have denounced racism and say their events are open to all races.

Cops released photos of seized weapons including bear mace, clubs, gloves with reinforced knuckles, batons, knives and handgun clips. It is unclear which side the weapons were seized from.

Portland police released these photos of weapons seized from the marchers. It's unclear which side was carrying them

Police roll in to disperse clashing protesters after revoking Patriot Prayer's permit to march on Saturday in Portland

Police announced that Patriot Prayer's march permit had been revoked at around 5.50pm, after saying 'Fireworks and other objects are being thrown at today's protest around 2nd and Main'.

Those arrested in the clashes were named as:

Luiz Enrique Marquez, 46, charged with first-degree theft, third-degree theft, and third-degree assault

Tusitala J. Toese, 22, charged with fourth-degree assault

Donovon Lyle Flippo, 23, charged with second-degree disorderly conduct

Matthew Reid Braddock, 37, charged with second-degree robbery and third-degree assault

According to booking records, all were released without bond with the exception of Braddock, whose bail has been set at $255,000.

Arrested (left to right): Luiz Enrique Marquez, Tusitala J. Toese, Donovon Lyle Flippo, Matthew Reid Braddock

Police restrain a man from the march by Patriot Prayer in Portland, Oregon, on Saturday. Police dispersed clashing protesters as problems occurred when two opposing protest groups Patriot Prayer and Antifa took to the streets

'Portland Police planned for today's protest so that people could exercise their First Amendment rights to speech and assembly,' said Deputy Chief Bob Day in a statement.

'We seized numerous weapons early on, and interceded and separated people when necessary. However, once projectiles, such as fireworks, eggs, rocks, bottles and construction equipment were thrown and people were injured, we ordered people to disperse,' Day said.

Patriot Prayer describes itself as a conservative free speech group that is open to all races.

The group's organizers, Joey Gibson, said in an interview with KOIN that the march was intended to show 'that there's a political move right now to have the police stand down in order to impact free speech in some of these big cities.'

'Portland's the last city on the West Coast that's doing that, so we just have to keep hitting it -- I don't see what else to do other than that,' Gibson said.

'We'll make Portland so ugly in terms of how they allow these protesters to charge us when we have a permit. The police stood down, we were told they would not stand down, so we have to challenge it.'

An organizer with Patriot Prayer is seen in Portland on Saturday before the violence broke out with Antifa

Right-wing marchers are seen at the rally, which organizers said was to protest lack of police protection at earlier rallies

Left-wing critics believe that Patriot Prayer is a 'fascist' organization and put out the call for the march to be disrupted before Saturday's events.

'Joey Gibson and his crew of violent bigots unfortunately are once again calling for a rally in Portland which is without fail a pretext for assorted Alt Right bullies, Nazis, homophobes, and unsavory characters to gather in hopes of brutalizing the most vulnerable people they can find,' a group called Eugene City Antifa said in a call on Facebook to disrupt the rally.

'It is very important that antifascists keep up the pressure so that we can stop them once and for all.'

'The priority for tomorrow is to make Joey and the fascists he brings in have such an awful time that they decide to stop having these events entirely,' Portland-based group Rose City Antifa said on Facebook on Friday.

'There are many ways in which to do this, and we will all have to use our various skills and take whatever opportunities present themselves.'