A crazed gunman was taken into custody Saturday night after allegedly opening fire on thousands of protesters during a "No Kings" march, that left one person critically injured, Utah police said.

The terrifying incident in Salt Lake City unfolded around 8 p.m., sending a crowd of more than 10,000 people running for their lives as gunshots rang out, according to local reports.

One person was rushed to the hospital with life-threatening injuries, the Salt Lake City Police Department said on X.

"We are investigating a shooting possibly associated with the demonstration near 200 South State Street," police said.

"We have a person of interest in custody. We are asking people to leave the demonstration safely and orderly."

The man who was taken into custody had blood on his hands, Fox 13 News reported.

The shooting remains under investigation.

Protesters continue to face off with police in a haze of tear gas outside a federal building in downtown Los Angeles, prompting officials to declare an unlawful assembly.

The Los Angeles Police Department said on X that protesters are throwing concrete, rocks, bottes and fireworks at officers.

A citywide curfew was set for 8 p.m. as the LAPD and other agencies aggressively moved to clear demonstrators from the streets after a seemingly peaceful "No Kings" rally erupted into a chaotic scene Saturday afternoon.

Footage showed police on horseback charging toward the crows while wielding their batons at demonstrators, with others in tactical gear firing off rounds of tear gas.

"We just wanted to come and support our people and we're getting tear gassed for it," Melissa Bran, 28, told the Associated Press while dabbing her red eyes with a wet cloth.

The boisterous crowd attending the US Army's 250th anniversary celebration joined together to sing "Happy Birthday" to President Trump -- after he called America the "hottest country in the world right now."

Trump, who turned 79 on Saturday, gave a roughly eight-minute speech boasting the courage and strength of the US armed forces.

"If you threaten the American people, our soldiers are coming for you," the commander in chief said.

"There is no earthly force more powerful than the brave heart of the US military or an Army Ranger paratrooper, or Green Beret," he continued.

They are the best. They are the finest from Bunker Hill to San Juan Hill, from Gettysburg to Guadalcanal, from Yorktown to Shiloh, and from the trenches of the Argonne to the mountains of Afghanistan, the Army has forged a legacy of unmatched courage, untold sacrifice.”

Trump also defended the roughly $45 million price tag of the massive military parade in Washington, DC.

"Every other country celebrates their victories. It's about time America did that too," he said.

The nearly three-hour event wrapped with an elaborate fireworks show over the National Mall, accompanied by 'The Army Song'

Vice President JD Vance urged the US Army to "kick the hell out of the enemy" as he took the stage during the military group's 250th anniversary celebration Saturday night.

The Marine veteran also told soldiers serving overseas to "come home safely," wished President Trump a very happy birthday and his wife, Usha, a happy anniversary.

The Army's multi-million dollar parade coincides with Trump's 79th birthday.

Country music star Warren Zeiders performed at the US Army's 250th anniversary military parade in Washington, DC, Saturday afternoon.

He performed "Ride the Lightning" and other hits in a performance that had the mass crowd and social media buzzing.

Los Angeles police fired tear gas into a crowd of protestors after a once-calm "No Kings" rally outside a downtown federal building erupted into chaos.

Photos and videos showed cops on horseback charging the crowd, striking some demonstrators with rods and batons as more than a 1,000 police officers in armored vehicles attempted to clear a street outside Edward R. Roybal Federal Building Saturday afternoon.

Authorities in gas mask then unleashed mace and crowd-control rounds, sending protestors and bystanders scrambling through the streets, the Associated Press reported.

"It was a total 100% over-reaction," Samantha Edgerton, 37, told the outlet.

"We weren't doing anything but standing around chanting peaceful protest."

Volunteer medics are on the ground offering saline solution to those in need.

President Trump looked on as thousands of troops and more than 100 tanks rumbled through the rainy streets of Washington, DC, Saturday for the Army’s 250th anniversary parade. 

The processions honoring the Army’s history began just before 6:30 p.m., starting with troops and drum and fife players in colonial-era livery worn during the Revolutionary War. 

An Army Golden Knights parachute team made a spectacular entrance during the portion of the parade honoring the 18th-century era troops, with several jumpers landing in the Ellipse near the White House.

Troops from the 4th Infantry Division followed, representing the Civil War-era of the Army, complete with cavalry soldiers. 

Soldiers clad in World War I and World War II era uniforms marched down Constitution Avenue, along the National Mall, next. 

Those processions included several pieces of iconic rolling stock from the period, including a 1918 Dodge touring car, Jeep scot cars, a Renault tank and several M4 “Sherman” tanks. 

A B-25 Mitchell bomber – the same aircraft used to carry out the Doolittle Raid over Japan – flanked by two P-51 Mustangs performed a flyover over the parade to cap the celebration of the era. 

The Vietnam War section of the parade began with a helicopter flyover. 

Massive M1 Abrams tanks lumbered past the president during the the Gulf War-era procession, their treads creaking as they rolled down the avenue.  

The Global War on Terror and Modern Era part of the parade showcased some of the Army’s newer heavy artillery, including Bradley Fighting Vehicles, Infantry Squad Vehicles and self-propelled Howitzers. 

The final sections of marching troops represented the Army’s future, and included small drones flying over the heads of soldiers and robot dogs in camouflage paint.

Instrumental versions of Journey's "Separate Ways (Worlds Apart)" and Heart's "Barracuda" were among the songs blared during the festivities.

Trump, with first lady Melania and Defense Secretary Pete Hegseth by his side, saluted to service members as they strolled past the reviewing stand. 

The president, who also celebrated his 79th birthday Friday, was surrounded by several family members, administration officials and Republican lawmakers in the VIP booth. 

As the president and first lady took the stage before the start of the parade a group of individuals wearing “250 special guest” badges across the street from the reviewing stand began singing “Happy Birthday.” 

The parade, estimated to cost between $25 to $45 million to put on, was sponsored by several corporations that received shout-outs during the processions, including Lockheed Martin, Coinbase, Palantir and the Ultimate Fighting Championship (UFC).

A raging maniac was arrested after he plowed his car into a crowd of protesters during a "No Kings" march in Virginia Saturday afternoon, the Culpeper Police Department announced.

Joseph Checklick Jr., 21, is accused of intentionally speeding his SUV through the crowd as they were leaving the rally and striking at least one person near James Madison Highway in Culpeper County.

No other injuries were reported.

He was charged with reckless driving and is being held without bond at the Culpeper County Jail.

President Trump and first lady Melania Trump are surrounded by family while they attend the Army's 250th anniversary parade — which falls on the president's birthday.

The president sported a navy blue suit, with a white collared shirt and his signature red tie, with Melania donning a white, pin-striped outfit with gray pumps.

Eric Trump, his wife Laura and their children, along with Tiffany Trump and her husband Michael Boulos, also left the White House with POTUS ahead of the festive celebration.

Saturday's multi-million dollar parade at the National Mall corresponds with Trump's 79th birthday.