US President Donald Trump has branded the Democratic mayor of Kenosha "a fool", accusing him of standing up for "radical anarchists".
Speaking en route to the city, Mr Trump said Kenosha would have been burnt to the ground by protesters were it not for the National Guard he deployed.
The Wisconsin city saw days of violence after Jacob Blake, a black man, was shot in the back by police.
Local leaders have asked the president to stay away.
But Mr Trump has ignored their pleas as he pushed a strong "law and order" message ahead of November's election.
"I think a lot of people are looking at what's happening to these Democrat-run cities and they're disgusted," the president said before boarding Air Force One to fly to Wisconsin.
"They see what's going on and they can't believe what's taking place in our country. I can't believe it either."
Although Mr Trump claimed he sent the National Guard into Kenosha, they were actually deployed by Wisconsin's governor.
He cited reports that protesters had tried to break into the house of Kenosha's Democratic Mayor John Antaramian.
"I saw last night where these radical anarchists are trying to get into the mayor's house and lots of bad things were happening to this poor foolish, very stupid mayor. I mean how he can be mayor I have no idea.
"They had tremendous numbers of people really harassing him horribly and I guess trying to break into his house and he still sticks up for them because he's a fool. Only a fool would stick up for them like that."
The claim of the break-in attempt is unconfirmed.
Mr Trump said he was visiting the city "for law enforcement and for the National Guard".
"They've done a great job in Kenosha. They have put out the flame immediately," he said.
In Kenosha the president will meet police officers but not the Blake family. He said previously it was because relatives had wanted lawyers present.
Over the weekend Mayor Antaramian said it was not a good time for Mr Trump to visit.
"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.