Murders committed by white supremacist groups doubled in 2017 compared to 2016, according to a new report by the Anti Defamation League.

The report, cited by the Jerusalem Post, says homicides by white supremacists have become more rampant than those by domestic Islamic extremists, and, that white supremacists and other far-right extremists were responsible for 59 per cent of all extremist-related fatalities in the US in 2017.

That is up from just 20 per cent of murders committed by far right extremists last year.

In addition, over the past 10 years, the report says, 71 per cent of the extremist fatalities were linked to domestic right-wing extremists, while 26 per cent were slain by Islamic extremists.

James Alex Fields Jr. (left) is accused of the deadly car ramming incident during a white supremacist rally in Charlottesville (left) in August of 2017

Sayfullo Saipov (right) is accused of the largest extremist attack in the US in 2017 in a car ramming incident in NYC (left) that killed eight- but the overall murders by all extremist groups in the US last year show murders by far right groups far ahead of Islamic extremists

The largest single deadly extremist attack in the US in 2017 however was the alleged attack by Islamic extremist Sayfullo Saipov whose car ramming incident in New York City killed eight people in late October.

The other alleged car-ramming attack was by a 'white supremacist in Charlottesville [in Virginia]' by James Alex Fields Jr. in August.

The report, titled 'Murder and Extremism in the United States in 2017' and published by the ADL's Center on Extremism, says this is the fifth deadliest year for US extremist violence since 1970.

'These findings are a stark reminder that domestic extremism is a serious threat to our safety and security,' said Jonathan A. Greenblatt, the ADL's CEO.

'The number of deaths attributed to white supremacists increased substantially. The bottom line is we cannot ignore one form of extremism over another. We must tackle them all,' he said.

One of the key findings in the report is that of 18 murders committed by white supremacists, several of them were linked to the 'alt right as that movement expanded its operations in 2017 from the Internet into the physical world – raising the likely possibility of more such violent acts in the future.'

'We cannot ignore the fact that white supremacists are emboldened, and as a society we need to keep a close watch on recruitment and rallies such as [that in] Charlottesville, which have the greatest potential to provoke and inspire violence.'

File photo of white supremacists in Charlottsville: Over the past 10 years white supremacists and far right extremists were responsible for 71 per cent of all extremist murders in the US, while Islamic extremists were responsible for 26 per cent

The ADL suggests all leaders from the president on down to small municipalities, use their power to stop the spread of hate.

'All civic leaders, from the president to mayors and police chiefs, must use their bully pulpit to speak out against racism, antisemitism and all forms of bigotry at every opportunity,' the ADL said.

'In addition, federal and state officials should support properly crafted programs to counter all forms of violent extremism, including that stemming from both international terrorist organizations and domestic extremist movements, or to facilitate people interested in leaving extremist movements.

'This includes programs to thwart recruitment of disaffected or alienated Americans. And all law enforcement agencies should comprehensively collect and report hate crimes data to the FBI,' the ADL said.