By Alta Spells and Josh Campbell, CNN

(CNN) -- Mayor Ted Wheeler was tear gassed in downtown Portland early Thursday morning, according to video and posts on Twitter from a New York Times journalist.

The video shows Wheeler, wearing goggles and a face mask amid a crowd of people, hold his nose and close his eyes in distress as a cloud of tear gas drifts by him.

"It stings. It's hard to breathe. I can tell you with 100% honesty I saw nothing that provoked this response," Wheeler said to the Times camera. "I'm not afraid but I am pissed off."

It's unknown at this time who is responsible for deploying the tear gas and there is nothing to indicate the mayor was targeted. Portland Police said they did not deploy any CS gas, a commonly used type of tear gas.

CNN has reached out to the mayor's office for additional comment.

The video appeared to come after Wheeler joined crowds to listen to protesters and answer their questions in response to violent clashes between demonstrators and federal forces, whose camouflage, troop-like uniforms and aggressive tactics have exacerbated the protests.

"It is an unconstitutional occupation," Wheeler told the crowd. "The tactics that have been used by our federal officers are abhorrent. They did not act with probable cause, people are not being told who they are being arrested by, and you're been denied basic constitutional rights."

President Donald Trump said federal officers were sent to the city to protect federal property, but protesters and local leaders have strongly opposed their presence. Demonstrations, many of which have been peaceful, have been ongoing for more than 50 days.

"This is clearly a waste of federal resources and it's getting increasingly dangerous," Wheeler told CNN. "We did not ask the feds to be here. We do not want them here. They're not helping the situation. They're not appropriately trained, and we're demanding that they leave."

Fires and tear gas outside federal courthouse

Overnight into Thursday morning, CNN's team in Portland filmed a large gathering of protesters outside the federal courthouse. Among a mostly peaceful group, some protesters launched fireworks at the building and set several fires outside.

Each major provocation was met with a show of force by federal agents inside the building, who then launched tear gas into the crowd.

CNN witnessed a noticeably more measured response by federal agents compared to previous evenings. Rather than lining up in formation to march protesters back several blocks, federal agents used crowd dispersant projectiles and tear gas long enough to extinguish the flames that had been set, before retreating back into the federal building.

Portland Police said people threw flammable material and incendiary devices over a fence next to the courthouse, starting a large fire, while others breached the fence. Just after midnight, one person in the crowd threw a flaming item into the courthouse, police said.

At just after 12:30 a.m., Portland Police declared a riot due to the "violent conduct of the large group" and told the group to leave. Most refused, police said, and over the next several hours, Molotov cocktails were thrown at the federal building along with hundreds of projectiles. At least one assault was reported, police said.

The group slowly dissipated over the next few hours, police said. Portland Police said they made no arrests.

A vote to end police cooperation with federal agencies

The mayor's comments came after the state's US Attorney called for an investigation into why some protesters were taken by federal agents without badges and put into unmarked vehicles.

"That is a use of police force, federal police force for political ends," Wheeler said. "That is not an acceptable solution anywhere in America," the mayor told the crowd.

Some of the remarks from Wednesday's crowd echoed similar concerns.

"I've been violated repeatedly, I've been shot with tear gas and munition, my body is bruised and swollen," one protester who identified themselves as a high school administrator told the mayor. "I want to know what you're going to do, to commit to me -- as an educator committed to my community to make sure that my First Amendment right is upheld?"

The mayor responded: "I will absolutely do everything in my power to go get rid of the federal troops and to reform the Portland Police Bureau. We need to do both."

Earlier on Wednesday, a unanimous Portland City Council voted to end cooperation between the Portland Police Bureau and federal agencies charged with protecting federal properties on Wednesday, Commissioner Chloe Eudaly said in a statement.

"Today, I introduced two resolutions -- one to cease all cooperation between the Portland Police Bureau and the federal occupiers, and one affirming the rights of members of the press and legal observers covering the protests against police brutality." the statement read.

"I am pleased to share that both of those resolutions were adopted unanimously by City Council."

Eudaly said the resolution could serve as both an example for other cities and a "national call to action."

"I stand in solidarity with protesters defending Black lives, demanding racial justice, and the transformation of our justice system, but whether you agree with the protesters or not, if you believe in the Constitution of the United States, you must oppose the actions of this President and the violent suppression of individuals exercising their constitutional rights," Eudaly said."