Far-right groups are rallying in the north-western US city of Portland, Oregon, amid fears of clashes with left-wing counter-protesters.
Police are mounting a major operation to keep the two sides apart.
The stated aim of the far-right gathering is to urge that the antifa (anti-fascist) movement be declared a domestic terror organisation.
Portland, one of the most liberal cities in the US, is regarded as an antifa stronghold.
Who's attending the rallies?
The rally has mainly been promoted by Joe Biggs, a member of the far-right Proud Boys group and former employee of Alex Jones's Infowars.
Proud Boys - which The Southern Poverty Law Center, a major US civil rights organisation, has classified as a hate group - have been involved in previous far-right rallies, and violent street clashes, in Portland.
Proud Boys says incidents of violence allegedly involving members of the loosely organised antifa movement, an international coalition of militant activists and protesters opposed to the far right - justifies a ban.
Members of the local Rose City Antifa group are mounting a counter-demonstration in the city.
A statement on its website accuses far-right groups of planning "to bring their branded political violence to our streets" and encourages people "to defend Portland against far-right attack".
As well as Proud Boys, a number of other far-right groups have said they will be there - for example the American Guard, which the Anti-Defamation League has called "hardcore white supremacist", and the militia group Three Percenters.
What's the background?
It follows two years of increasingly violent rallies in Portland, many of which were organised by Joey Gibson, the leader of far-right group Patriot Prayer, who is currently facing criminal charges connected to a right-wing riot outside a bar in May.
But organisers claim this particular rally is a response to an incident said to have taken place at the last far-right rally held in the city, in June. Then, the right-wing writer Andy Ngo had milkshakes thrown at him and was punched by counter-protesters.
President Donald Trump has said the Portland situation is being closely watched by his administration, and indicated that naming antifa "an organisation of terror" was being considered.
Mr Trump has previously mentioned white supremacists, as well as antifa as being a major issue.