Congressman Eric Swalwell will announce next week that he is running for US president with a campaign focused on gun control, it was reported on Thursday.

The 38-year-old will declare during an appearance on CBS’s The Late Show with Stephen Colbert where he will be joined by Cameron Kasky, a survivor of last year’s mass shooting at Marjory Stoneman Douglas high school in Parkland, Florida, according to the Atlantic magazine.

Swalwell, who is also hosting a town hall on gun control next week in Florida, told the Atlantic: “ I do believe that gun safety has to be a top 2020 issue.”

The shooting at Marjory Stoneman Douglas left 17 people dead and another 17 injured. It sparked the March for Our Lives, formed by survivors of the shooting who have demanded stricter gun control legislation.

Last year Swalwell wrote a column about how the March for Our Lives movement inspired his call to ban all assault weapons.

There are already 17 Democrats running for president – congressman Tim Ryan also entered the fray on Thursday – with former vice-president Joe Biden also expected to soon join. Swalwell, a fourth-term congressman from northern California, would potentially follow the playbook of Jay Inslee, the governor of Washington state, by differentiating himself with a laser-like concentration on a single issue – in Inslee’s case, climate change.

He has just pinned a tweet at the top of his Twitter page with a voicemail from a man abusing him over his activism for gun control. The politician writes defiantly: “I’m not afraid of this guy. I’m not afraid of the NRA. I’m not afraid. No fear.”

And last week he tweeted photos of himself with Shannon Watts, the founder of Moms Demand Action for Gun Sense in America, at an annual event with veterans at a shooting range.

Swalwell has hinted for months that he is considering a bid for the Democratic presidential nomination in 2020 and has become a familiar face in the early voting states Iowa and New Hampshire.

The Late Show with Stephen Colbert has become a popular stop for candidates prompting the label “the Colbert primary”. Senator Kirsten Gillibrand appeared on it to announce she was forming an exploratory committee. Cory Booker, Beto O’Rourke, Amy Klobuchar, Bernie Sanders, Julián Castro, Kamala Harris and Stacey Abrams have all been guests.