Thousands of people gathered in Downtown Las Vegas for a "No Kings Day" protest, part of a nationwide action to rally against President Donald Trump.

People were urged to gather outside the Lloyd George Federal Building on Las Vegas Boulevard to protest what organizers called Trump's authoritarian policies.

After the main protest concluded, dozens of people trickled toward the Fremont Street Experience to the north and The STRAT to the south to continue voicing their opposition to the president.

Las Vegas Metropolitan Police estimated 8,000 people were in attendance, and only 15 arrests were made in connection with the protest. Four of those arrested were juveniles.

One person was arrested for felony assault with a deadly weapon, and one was arrested for possession of a dangerous weapon, a gross misdemeanor. There was no word on what led to the other arrests.

Throughout the day, protesters said they wanted to denounce the Trump administration's actions, including recent hard-line immigration enforcement and cracking down on protesters in Los Angeles.

Tiana Elliott carried a sign reading "Billionaires take more money than they give." She said she was opposed to Saturday's military parade in Washington D.C. to celebrate the Army's 250th birthday. The day also happens to be Trump's 79th birthday.

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"I don't really care what it's for," Elliott said about the parade. "It's too much money to be spent. That is our money, that should be going towards the people."

Bernie Loomis said he's a Navy veteran, but he is worried the U.S. is headed toward a dictatorship.

"Take a look at what happened in California," he said. "They had the military out there manhandling people. They had a senator that was put on the floor. That is not right. This administration is way out of line. They've crossed the Rubicon."

U.S. Rep. Dina Titus, D-Nevada, attended the rally and spoke to protesters as well. She told News 3 she wanted to send a message that America is founded on the principles of democracy.

"You have a Constitution that's been in place a long time, and we should follow it," Titus said. "When you have a president who just ignores it and says, 'I don't know if it's my job to follow the Constitution,' then there's something wrong. That's not American."

A separate protest was also held earlier in the morning on the Las Vegas Strip.

Dozens of Las Vegas Metropolitan Police officers were seen observing the protest. LVMPD and other officials have urged people to protest peacefully, saying any signs of violence or destruction of property could be met with force.

This comes after police used pepperballs and other methods to disperse a protest in Downtown Las Vegas on Wednesday after declaring it "unlawful."

One officer on Saturday could be heard yelling through a bullhorn for people to stay on the sidewalk. LVMPD later said they have shut down traffic on Las Vegas Boulevard at Bonneville and Clark avenues because of the protest.

The protest has been almost entirely peaceful. Steve Grammas, president of the Las Vegas Police Protective Association, told News 3 that he had received no reports of violence toward officers on scene.

Still, multiple people were seen being detained during Saturday's protest. One man wearing a face covering was taken into custody at Las Vegas Boulevard and Bridger Avenue. Another man was seen being led to a police vehicle with his hands zip-tied behind his back.

Someone at the protest told News 3 that he tried to flag officers to a person with a knife before that person was taken into custody.

More people were detained at the Fremont Street Experience as well.

There is also concern about people's safety amid the triple-digit heat. At least one person could be seen receiving first aid treatment.