A Republican congressman from Louisiana has come under fire for a Facebook post he wrote after the London terror attacks this weekend, calling for all radical Muslims to be hunted down and killed.

Rep. Clay Higgins - dubbed the 'Cajun John Wayne' - wrote the post on Sunday, the day after the attack on London Bridge and Borough Market that left seven dead.

'The free world... all of Christendom... is at war with Islamic horror,' Higgins wrote in the post, above a picture of a victim on the ground outside of a pub.

'Not one penny of American treasure should be granted to any nation who harbors these heathen animals. Not a single radicalized Islamic suspect should be granted any measure of quarter. Their intended entry to the American homeland should be summarily denied.

'Every conceivable measure should be engaged to hunt them down. Hunt them, identify them, and kill them. Kill them all. For the sake of all that is good and righteous. Kill them all,' Higgins added.

Louisiana Congressman Clay Higgins has come under fire for a post he wrote after the London terror attacks this weekend

In the Sunday post, Higgins said that all radical Muslims should be hunted down and killed

Higgins' post quickly went viral, with more than 2,500 users commenting on it.

The top-rated comments were by and large negative, with many calling Higgins' post hate speech and verging on genocidal.

'This is extremely hateful,' user Tyler F. Thigpen wrote. 'I didn't vote for you, but you represent me and I'd like to hear a lot less hateful speech from the politicians that serve me. Your disparaging rhetoric is disheartening and it's prime propaganda verbiage for the folks you're advocating we kill.'

Another user, Misty Johnson, added: 'Wow, you are no better than a terrorist. I'm more afraid of people like you than a refugee who was vetted for 2 years by 7 Intel agencies. I think we need better vetting for our representatives. You are an unhinged lunatic and playing right into what ISIS wants.'

But so far Higgins appears to have stood by his comments, refusing to take the post down.

And this is far from the first time that he has incited controversy.

Higgins' (pictured) post quickly went viral, with more than 2,500 Facebook users commenting

Higgins, an Army veteran and former police officer, was elected to Louisiana's third district in December

Higgins served as a military police officer in the Louisiana National Guard

Higgins resigned from his job as a captain for the St. Landry Parish Sheriff in 2016 because of public outcry over videos he made for Crime Stoppers, which targeted a local Louisiana gang and called them 'thugs,' 'animals,' and 'heathens'.

Before that, he resigned from the Opelousas Police Department right before he was set to be punished for using excessive force.

It was also revealed during Higgins' run for office that his first wife, who died in a car accident, claimed in their 1991 divorce that he once put a gun to her head.

Higgins said he had not contested the divorce and knew nothing of the allegation.

He said the marriage fell apart after the death of their six-month-old daughter. But, he insisted, there was no violence, no threats.

Now married to his fourth wife, Higgins is a New Orleans native. He grew up on a horse farm north of the city, achieved financial success in the automobile business and served in the Army National Guard as a military police officer. He says he began turning around an admittedly raucous lifestyle — 'I worked too much, I drank too much, I didn't honor my wedding vows' — after a divorce from his second wife and the resulting separation from their children.

He has slipped Bible references into some of his videos and wears wrist bands with the words 'Redemption' and tiny crosses.

Higgins was elected in a run-off between two Republicans in December, with 56 per cent of the vote. He represents Louisiana's third district, which is in the southwest of the state along the Gulf of Mexico. Every parish in the district voted for Donald Trump in the presidential election.