Children can be heard saying "Destroy them!" as they toss the masks into a burning barrel. A parent cautions the kids in the video not to throw in too many masks at once, telling them to "let them burn".
Darr Moon, husband of Republican Idaho state representative Dorothy Moon, told Mr Olmos: "We're standing here today to reign back government, to reestablish our Republican form of government, a government that has balance between the branches."
He added: "We need certain boundaries and that's not what we have today. Our governor is appropriating money and pretty much running the show here in Idaho."
Organisers said that similar "burn the mask" demonstrations were being held in 20 other Idaho cities.
Another organizer lead the crowd of around 150 people in pledging allegiance to the flag.
As police told protestors to put out the fire, they simply told the officers to "get out of here" and to leave organisers "alone".
According to data from CNN, Idaho has suffered worse from the pandemic compared to some of its neighbouring states. 105 out of every 100,000 people have died in the state compared to 54 in Oregon and 66 in Washington state.
The state recorded its first case of Covid-19 on 13 March 2020, according to KTVB. The state's Republican governor Brad Little slammed the efforts of his own party to roll back his Covid-19 emergency declaration in late January, CNN reported.
The Republicans control both the state house and state senate in Idaho.
Mr Little said: "I believe in my heart that what the Idaho Legislature is doing is harmful to our people and wrong for Idaho," adding, "I urge my partners in the Legislature to stop the political gains and do what is right for the people of Idaho".
Mr Little said the declaration was "critical" for the state to receive federal assistance.
The state senate later backed off the idea to end the emergency declaration, according to Boise State Public Radio.
Speaking to KTVB and looking back on his actions during the last year, Mr Litte said: "There were some federal programs that were directed to us that had we known earlier we could have prepared better."
He added: "The one thing I know for sure, the no-action alternative would have been a disaster. Nobody did that. You had to act given the magnitude of the pandemic."
Asked if he would open up the state fully like Texas and Mississippi, Mr Little said: "Texas and Mississippi are opening up to like where we are now. They're taking off their mask mandate. We don't have a mandate. They're opening up businesses that we have open. The only real issue in Idaho is gathering size, and as we check around with the hospitals to make sure they're okay, that will be the next thing."
Blasting President Joe Biden’s $1.9tn Covid-19 relief bill that passed the Senate on Saturday, Mr Little argued the bill would penalise states like Idaho which has remained largely open during the pandemic.
He said: "A quarter of a billion dollars of Idahoans' federal taxes would subsidize states that have kept people out of work! States such as California, New York, New Jersey, Illinois, and others would get more than their fair share under Biden's plan."
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