An Antifa activist has been filmed goading a riot police officer by flashing her bum at him during violent protests in Oregon.

The far-left, anti-fascist campaigner pulled her trousers down and shook her bare bottom just inches from the officer, who was armed with a baton and tried his best to look the other way.

She even tapped their a few times before spinning round and giving the stoic policeman the middle finger, telling him: 'F*** you, pig.'

An Antifa protester flashes her bum at a riot police officer who tries to look the other way

When that doesn't get his attention, the campaigner sticks a middle finger up at him and says: 'F*** you, pig'

At one point, in an attempt to get a reaction out of the officer, the protester bizarrely asked him: 'Do you have anal recognition software?'

Antifa had gathered in downtown Portland to oppose a protest by new men's rights movement Him Too, which aims to bring awareness to men who had been falsely accused of sex crimes.

Riot police were called in as clashes turned ugly, with six arrests being made.

The anti-fascist demonstrator even tapped her bum a few times and asked the policeman: 'Do you have anal recognition software?'

The stoic officer calmly tells her: 'The sidewalk is closed, please move into the park'

In the clip, the protester goads the officer by flashing her bum, while the cameraman can be heard shouting: 'Officer Bernard.'

When that doesn't get his attention, the flasher turns and sticks the middle finger up at him while shouting expletives.

The clip ends when the unfazed officer calmly tells her: 'The sidewalk is closed, please move into the park.'