WASHINGTON – Republican Rep. Ken Buck posted a video on Twitter Friday of him wielding an AR-15 in his office in Washington, D.C., and daring former Vice President Joe Biden and former Rep. Beto O'Rourke, D-Texas, to "come and take it."

"[I]f you want to take everyone’s AR-15s, why don’t you swing by my office in Washington, D.C. and start with this one?" the Colorado lawmaker said, while grabbing the gun, wrapped with American flags, off the wall.

Buck is alluding to comments O'Rourke made, when he was a Democratic candidate for president, during a debate last year.

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“Hell, yes, we’re going to take your AR-15, your AK-47,” O’Rourke said in response to a question about his proposal to buy back military-style assault weapons. The Democratic presidential debate took place a month after a gunman opened fire at a Walmart in his hometown of El Paso, killing 22 and injuring more.

Monday, after O'Rourke endorsed Biden for the nomination, Biden said of the former Texas congressman, "I want to make something clear. I'm gonna guarantee you, this is not the last you're seeing of this guy. You're gonna take care of the gun problem with me. You're going to be the one who leads this effort."

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Buck brought the gun to Capitol Hill in 2015, and said he submitted to local and federal regulations, taking away the capabilities necessary to actually fire the weapon. “The only dangerous thing about that gun is if someone took it off the wall and hit somebody else over the head with it," he said in 2015.

U.S. Capitol Police said then that members of Congress “may maintain firearms within the confines of their office.”

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Rep. Eric Swalwell, D-Calif., who is a fierce gun control advocate and used his platform as a 2020 Democratic presidential candidate to raise the issue, tweeted in response, "No one is coming for your inoperable gun, Ken. #ShootingBlanks."

Regardless, gun control advocates were quick to speak up about the video.

Rep. Haley Stevens, D-Mich., tweeted that, "This behavior is threatening and unacceptable. I feel unsafe with this in my place of work."

Fred Guttenberg, a gun violence activist whose daughter was killed in the Parkland, Florida, school shooting in 2018, responded that if he had "seen this yesterday when in DC I gladly would have. My daughter died from a single AR 15 bullet. You may find joy in that, I don't. I will gladly come back to DC to discuss your AR 15 and removing it for safe storage. Do not make threats of AR 15 violence."

Guttenberg, who is a well-known visitor to Capitol Hill advocating for gun violence prevention, was the man who interrupted President Donald Trump during his State of the Union address this year when Trump was touting support for gun rights. Guttenberg was escorted out of the chamber.

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Gun control activist Brandon Wolf, who is a survivor of the Pulse Nightclub shooting of 2016, quote-tweeted Buck's video, simply saying "@FBI : just wanted to ping you on this. Happy Friday!"

“I have always been a strong supporter of the 2nd Amendment and will continue to stand up to any attacks on the law-abiding gun owners of Colorado’s Fourth District,” Buck said in a statement Friday, further highlighting that Capitol Hill Police gave him permission to display the gun.

Contributing: Christal Hayes, Adrianna Rodriguez