A US senator has said some colleagues wore bulletproof vests as protesters with assault rifles entered the Michigan State Capitol on Thursday.
Hundreds of people, some of them armed, attended the "American Patriot Rally" against extending the coronavirus lockdown in the state.
Police allowed more than 100 to enter the building, where weapons are permitted.
Inside, they sang the national anthem and chanted "let us work".
Senator Dayna Polehanki tweeted a picture from the chamber of "men with rifles yelling at us".
"Some of my colleagues who own bulletproof vests are wearing them. I have never appreciated our Sergeants-at-Arms more than today," she said.
Pictures show another senator, Sylvia Santana, appearing to be wearing a vest under her jacket.
Photos show protesters ignoring social distancing and yelling at police to let them in the chamber.
They were demonstrating over a request by Michigan's governor to extend emergency powers to deal with the COVID-19 crisis.
The protesters want businesses to be allowed to reopen to get the economy going again.
But Gretchen Whitmer defied the state's Republican legislature and extended the lockdown to 28 May.
More than 3,700 people have died after being diagnosed with coronavirus in the state - the majority in the Detroit area - only New York and New Jersey have recorded more deaths.
The protest appeared to be the biggest in Michigan since thousands of Trump supporters jammed the streets around the capitol building two weeks ago for "Operation Gridlock".
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