Far-right Republican congresswoman Marjorie Taylor Greene has posted footage to Twitter in which she appears to kick an 18-year-old activist pressing her on gun control outside the Capitol in Washington.

The activist, Marianna Pecora, indicated she could press charges.

The encounter, in which Pecora and others asked about gun control in light of recent mass shootings in the US, happened as the Georgia congresswoman left the Capitol on Thursday. Greene has championed gun rights.

In her tweet, Greene wrote: “These foolish cowards want the government to take away guns and the rights of parents to defend their children in schools.

“You have to be an idiot to think gun control will create a utopian society where criminals disarm themselves and obey the law. ‘Gun-free’ zones kill people.”

Pecora is deputy communications director for the group Voters of Tomorrow.

On Twitter, she said: “Our team is in DC this week to lobby for youth rights. All the members of Congress we’ve met with so far (both Republicans and Democrats) have been nothing but respectful – except for Marjorie Taylor Greene. She kicked me.”

In the footage, Pecora and others argue with Greene and film with their phones. Pecora walks in front of Greene, who appears to tread on her heel. Greene repeats “excuse me” and appears to kick Pecora’s leg from behind.

Pecora then protests and Greene waves her off.

Nick Dyer, Greene’s communications director, says: “You’re blocking a member of Congress. You can’t block members of Congress.”

On Twitter, Pecora said she “started out Hispanic Heritage Month by getting kicked by [Greene]. I’ve never been prouder to be a Mexican-American.”

She also wrote: “First month living in DC and I get featured in” the Washington Post.

Pecora told the paper: “It’s honestly, like, really disheartening to think that a bunch of kids can hold themselves with better composure than a sitting member of Congress.”

The Post said Dyer “voiced objections to the description of the video and described a version of events unsubstantiated by video evidence”.

Greene has initiated other public confrontations, including harassing the gun control campaigner David Hogg, also 18 at the time, and the New York Democrat Alexandria Ocasio-Cortez, incidents that achieved online infamy of their own.

Pecora pointed to a message from Santiago Mayer, the Mexican-born founder of Voters for Tomorrow whom Greene said should “move to another country”.

Mayer wrote: “To answer the most prevalent question about pressing charges: we’re talking to our legal team and keeping our options open. Love y’all.”