Protesters swarmed Denver on Thursday, blocking traffic and smashing vehicles while running from gunfire and police tear gas after a demonstration against the death of a black man in Minneapolis police custody turned violent.

Hundreds of demonstrators stood in the downtown streets and chanted as darkness fell outside the Colorado State Capitol, where protesters spray-painted graffiti and broke car windows. In other areas of downtown Denver, police in riot gear fired gas canisters, used rubber bullets and walked in a phalanx through the streets to drive protesters away. The protest briefly spilled over onto Interstate 25, blocking all lanes of traffic until police used tear gas to disperse the crowd.

The protests continued into the night, despite Denver Mayor Michael Hancock pleading for calm.

“I certainly understand everyone’s frustration and sense of pain and disgust following the murder of George Floyd in Minneapolis,” he said in a video posted on Twitter. “But I want to plead to everyone. Let’s demonstrate, but let’s demonstrate peacefully. Leave the weapons home.”

Earlier in the protest, gunfire outside the state Capitol sent people running for cover. Gary Cutler, a spokesman for the Colorado State Patrol, said the shots were fired in a park across the street. Most of the protesters already had left the area and were marching downtown.

Cutler said the Capitol building was locked down, and everyone inside was safe. No injuries have been reported from the shots.

State Rep. Leslie Herod, who was protesting at the Capitol, tweeted, “We just got shot at.” She later said, “We will not be deterred by this unspeakable act of violence.”

Police spokesman Kurt Barnes said it’s unclear if the protesters were being targeted, and no one has been arrested.

About six or seven shots were fired, he said.

Several hundred protesters had gathered to call for justice following the death of Floyd, who died in police custody in Minneapolis on Monday after an officer knelt on his neck for almost eight minutes. In footage recorded by a bystander, Floyd pleaded that he couldn’t breathe.

Some among the Denver protesters carried signs reading “Black Lives Matter” and chanted, “Hey, hey. Ho, ho. Racist police got to go.”

Aerial footage showed several protesters smashing the windows out of at least two vehicles parked outside the Capitol, and others spray-painted graffiti on the Capitol steps.

A cellphone video shot by protester Anabel Escobar, 29, showed a man on the hood of an SUV making its way through the crowd in front of the Capitol. The video showed the driver speeding up and then apparently trying to run the man over after he fell off the hood. The vehicle sped away as other protesters chased it. It was unclear if the man on the hood was injured.

Gov. Jared Polis said Thursday night he was “absolutely shocked” by the video.

“Coloradans are better than this,” he said. “I share the immense anguish we all feel about the unjust murder of George Floyd. But let me be clear, senseless violence will never be healed by more violence.”

As the protest started, The Denver Police Department tweeted a message from Chief Paul Pazen sending condolences to Floyd’s family and saying the city’s officers do not use the tactics employed by the Minneapolis officers.

He called that type of force “inexcusable.”

Four Minneapolis police officers have been fired, and the mayor has called for the officer who knelt on Floyd’s neck to be criminally charged.

The death has led to violent protests in Minneapolis and demonstrations in other cities, including Los Angeles.