The Arizona Department of Public Safety estimated about 6,000 people gathered near the Capitol on June 14 for the anti-Trump "No Kings" protest.

An armed man arrested Saturday during Nashville’s “No Kings” protest has a long history of fascination with Nazis and mass murderers, and he was already on the FBI's radar, NewsChannel 5 Investigates has learned.

Thousands marched and rallied peacefully during the No Kings OKC protest on June 14, the same day as the U.S. Army 250th Anniversary military parade.

It remained unclear why Kevin Krebs, of Malvern, brought the weapons to the protest. Prosecutors say their investigation is ongoing.

In Los Angeles, 38 people were arrested downtown on Saturday night, police said Sunday. In Huntington Beach, police arrested a convicted felon they said had a loaded handgun.

The largely peaceful protests during the "No Kings Day" demonstration in downtown Los Angeles took an intense turn in the afternoon. Police ordered the crowd to disperse at about 4:15 p.m. PDT near Alameda Street and Temple Avenue, according to the Los Angeles Police Department's Central Division.

Millions of people turned out for "No Kings" protests nationwide on Saturday that were largely peaceful though there were some arrests and police had to disperse unruly crowds, including in Georgia and Los Angeles.