Back on the campaign trail after a 12-day hiatus - grieving the lives lost following a mass shooting in his hometown El Paso - US presidential candidate Beto O'Rourke has visited a gun show in Arkansas.

The Democratic hopeful spoke to gun owners and sellers a day after announcing his plan to combat gun violence, and said he "appreciated hearing their perspectives" at the Little Rock event.

In Arkansas, I listened to gun owners and sellers—and appreciated hearing their perspectives. But as the plan we released yesterday says, if I’m president, you wouldn’t be able to buy weapons of war for $395. You wouldn’t be able to buy them at all. pic.twitter.com/Pz8KuFq9Tt — Beto O'Rourke (@BetoORourke) August 17, 2019

"But as the plan we released yesterday says, if I'm President, you wouldn't be able to buy weapons of war for $395," he said on Twitter.

"You wouldn't be able to buy them at all."

The National Rifle Association quickly fired back, quoting the candidate's tweet in a tweet of its own, and asked Mr O'Rourke if he had seen the polls.

“If I’m president...”



Beto: Have you taken a look at the polls? 🤣 https://t.co/BfwRQdXVdd — NRA (@NRA) August 17, 2019

Mr O'Rourke responded: "70 per cent of Americans supported an assault weapons ban, including most Republicans".

The visit came a day after Mr O'Rourke revealed a sweeping plan for gun control. It includes the assault weapons ban, mandatory buybacks for assault weapons, thorough background checks, a renewed gun-licensing and registry system, and a plan to tackle white supremacy.

Responding to the visit, Mr O'Rourke's team said it was important the campaign reached all Americans.

AAP

"In a democracy and in this country, I hope, you're never allowed to write anybody off because they're a Republican, because they're a gun seller, because they're at a gun show," a statement read.

"In fact, if you want to solve and address these challenges, listen to the people who understand it perhaps in some ways better than anybody."