A white supremacist group hung a banner over a Bay Bridge tunnel in San Francisco in protest of its sanctuary city policy.

The sign, placed above the entrance to the Yerba Buena Tunnel, said 'DANGER' in bold red letters and 'Sanctuary City Ahead' with skull and cross bones on either side and 'Identity Evropa' underneath.

It could be seen by those driving west on Interstate 80 early on Sunday, but was quickly removed, SFGate reports.

A white supremacist group hung a banner over a Bay Bridge tunnel in San Francisco in protest of its sanctuary city policy

Officer Vu Williams, of the California Highway Patrol, told the website that the sign was only visible 'very briefly' but said it was not clear who removed it.

Identity Evropa shared pictures of the sign on Twitter on Sunday, writing: 'PUBLIC SERVICE ANNOUNCEMENT FROM IDENTITY EVROPA San Francisco is a dangerous sanctuary city where the law does not apply to illegal invaders.'

It added: 'Enter at your own risk!'

According to the Southern Poverty Law Center, Identity Evropa is a white nationalist organization and designated as a hate group.

The sign, placed above the entrance to the Yerba Buena Tunnel, said 'DANGER' in bold red letters and 'Sanctuary City Ahead'

Identity Evropa took credit for the sign and shared pictures on Twitter on Sunday morning

The group 'peddle the delusion of white genocide' and attempt to recruit white college-age students, according to the law center.

It was founded by Nathan Damigo, a 31-year-old former Marine while he was studying at the California State University at Stanislaus in 2016.

He made headlines last year after he punched a woman in the face during a confrontation at an alt-right rally in Berkeley.

Damigo also helped organize the Unite the Right rally in Charlottesville, Virginia, where 32-year-old Heather Heyer was killed by a man who drove a car into a crowd of counter-protesters.

Identity Evropa was founded by Nathan Damigo (pictured), a 31-year-old former Marine while he was studying at the California State University at Stanislaus in 2016.

His father Peter Lodge, an adjunct history professor at the University of Maine, spoke out after his son's involvement in the rally was reported.

'I completely disavow his activities with the racist organizations,' he said, according to the Lewiston-Auburn Sun Journal.

'In no way do I support any racist organization. I have spent my life trying to bring people of all groups together regardless of race or sexual preference, to make the world better.

'I'm afraid I could not have the same influence on my son.'

White nationalists carrying the Identity Evropa flag are pictured arriving at a rally in Charlottesville, Virginia, on August 12 last year

On its own website, Identity Evropa describes itself as 'a generation of awakened Europeans who have discovered that we are part of the great peoples, history, and civilization that flowed from the European continent.'

The group also describes itself as a 'secular organization' with members who practice a 'diverse range of traditional European faiths.'

However, its membership application stipulates that applicants must be of 'European, non-Semitic' heritage.

DailyMail.com has contacted Identity Evropa for comment.