Image copyright AFP/Getty Image caption Oregon is one of the areas in the Pacific Northwest worst affected by the raging wildfires

Misinformation about wildfires raging across the US state of Oregon has been rife on social media, prompting local officials to try to dispel the rumours.

Unsubstantiated online claims blamed the fires on activists from two fringe groups - antifa, short for "anti-fascist", and the nationalist Proud Boys group.

Both groups have been accused by politicians, law enforcement and some commentators of encouraging and participating in violence during anti-racism protests in the US, including regular confrontations in Portland, Oregon's largest city.

Dozens of posts with bogus wildfire allegations were shared across multiple social networks - the most popular were shared thousands of times.

As a result, some local law enforcement agencies say they have been overwhelmed with requests based on false information.