US President Donald Trump has branded the Democratic mayor of Kenosha, Wisconsin, John Antaramian, a fool, accusing him of defending "radical anarchists," BBC News reported.

Trump visited Kenosha to back law enforcement after the police shooting of a black man sparked civil strife.

The Republican president blamed "domestic terror" for the "destruction" in the Midwestern city.

Kenosha saw days of violence after police shot Jacob Blake in the back and left him paralyzed on 23 August.

Opinion polls show Trump is narrowing Democratic rival Joe Biden's lead ahead of November's election.

The president is pushing a strong "law and order" message. Biden has accused Trump of stoking racial division.

Over the weekend, however, Kenosha Mayor John Antaramian said it was not a good time for Trump to visit the city. "Realistically, from our perspective, our preference would have been for him not to be coming at this point in time," he told National Public Radio.

Wisconsin's Democratic Governor Tony Evers also warned against the visit, saying it would "hinder our healing."