New York: A brawl outside a Republican club in Manhattan involving a far-right group and anti-fascist activists spurred calls for an investigation into the violence and whether police acted properly in breaking it up.

Some Democratic politicians, including New York Governor Andrew Cuomo, also criticised the club for inviting Gavin McInnes, the head of the far-right group, the Proud Boys.

Cuomo has now asked for the FBI to look into the incident, and assigned a State Police hate crimes unit to assist with the New York Police Department investigation of the violence, which he linked to President Donald Trump.

"This is Trump at his worst," the governor said on a call with reporters. "It is wholly consistent with everything he has done since he started running for president."