Police in Washington state have arrested an armed right-wing protester on charges of first-degree assault Saturday in Olympia, the state capital, on suspicion of shooting a left-wing protester during demonstrations fueled by baseless claims that President Trump had been wrongly denied reelection.

Authorities identified the alleged shooter as a 25-year-old man from Shoreline, a city north of Seattle, but did not release a name. He remains in custody.

The shooting, which occurred shortly after 2 p.m., was the second in just eight days in Olympia as protests and counterprotests related to Trump’s election defeat and false claims of voter fraud have escalated into violence, as they have in the nation’s capital, where at least four people were reportedly stabbed Saturday night.

In Olympia on Saturday, demonstrations between supporters and opponents of Trump rapidly deteriorated into rioting and violence, moving between the sprawling State Capitol grounds and downtown streets, said Chris Loftis, a spokesman for the Washington State Patrol, which is investigating the shooting.

The victim is in a hospital but has refused to speak to investigators, and the extent of the person’s injuries is unknown.

“This was very different yesterday than anything we’ve seen before,” said Loftis, adding that the previous weekend’s shooting, by a right-wing protester into a crowd of left-wing demonstrators, produced no serious injuries. He declined to name the groups involved in either weekend’s protests and counterprotests.

The right-wing group that gathered Saturday, which included at least a few men wearing the trademark Hawaiian shirts of the “boogaloo boys” group calling for a second civil war, had 50 to 80 members, Loftis said, while the left-wing group had 130 to 150 members, most of them clad in black “tactical gear.” Members of both groups were heavily armed with long guns, pistols and knives.

“They were looking for confrontation,” Loftis said.

A report in the Olympian newspaper described the right-wing protesters as including Proud Boys, a male-chauvinist organization with ties to white nationalism, and other supporters of Trump. The left-wing protesters included members of the loosely organized antifa movement, the newspaper said.

Police also recovered an unexploded, commercial-grade firework that had been thrown into the crowd of protesters and counterprotesters.