The National Rifle Association of America has defended a controversial new recruitment video that counter-terrorism experts have likened to extremist propaganda.

The ‘Violence of Lies’ advert released on Friday urged viewers to fight against the left with a “clenched fist”.

Despite overwhelming backlash and calls to remove the video, the NRA won’t apologise. Instead, a spokesman attacked viewers for their outrage, telling them to “get over it and grow up”.

“To every member of the violent Left that’s having a meltdown over Dana Loesch’s NRA ad, get over yourself,” the NRA’s Grant Stinchfield said in a follow-up video.

“You people openly call for the assassination of our president and then claim the NRA is inciting violence, you set fire to buildings and attack people in the streets and then go ballistic for being called out.”

He said an apology “would never happen”.

“To those of you on the violent left who claim we believe there is an ‘us and them’ in this country, you are absolutely right.

“There are those of us who actively believe in freedom, then there are those of you who actively burn down our country because you can’t get over [the fact that] your so-called ‘progressive’ didn’t win the election.”

The video has been widely denounced with some labelling it “the white equivalent of an ISIS recruitment video”, hateful propaganda and fuelling extremist movements.

Former CIA intelligence analyst Cynthia Storer wrote on Twitter that the “NRA is feeding an us vs them narrative of the kind that fuels all extremist movements”.

Watch the NRA advert below:

https://www.youtube.com/watch?v=WK_jkPhrddc

In the original minute-long YouTube video, conservative TV host Dana Loesch outraged gun control advocates and gun owners alike by provoking fear and a false narrative of the US political climate.

“They use their media to assassinate real news. They use their schools to teach children that their president is another Hitler. They use their movie stars and singers and award shows to repeat their narrative over and over again,” she said in the video.

“And then they use their ex-president to endorse the resistance. All to make them march, make them protest, make them scream racism and sexism and xenophobia and homophobia and smash windows, burn cars, shut down interstates and airports, bully and terrorise the law abiding — until the only option left is for police to do their jobs and stop the madness.

“The only way we stop this, the only way we save our country and our freedom is to fight this violence of lies with the clenched fist of truth.”

The video elicited strong reaction from the public, including a petition signed by almost 30,000 people to have the video removed from Facebook.

This NRA ad is an open call to violence to protect white supremacy. If I made a video like this, I’d be in jail. pic.twitter.com/LD65yMUMVn

— deray mckesson 4:44 (@deray) June 29, 2017

I think the @NRA is telling people to shoot us.

Now might be the right time to cancel your membership. pic.twitter.com/PWhHAvRcI3

— Chris Murphy (@ChrisMurphyCT) June 29, 2017

Hey, @NRA! I am a gun owner and I am appalled by that hate propaganda video you released. You are failing your members & the country.

— Alyssa Milano (@Alyssa_Milano) June 30, 2017

The video has generated more than 5.9 million views since its release.