Local officials said federal law enforcement, not police, fired the gas at protesters gathered outside a building of U.S. Immigration and Customs Enforcement.
Department of Homeland Security officers used teargas to disperse protesters in Portland and pointed guns at supporters of Black Lives Matter.
Senator Ted Cruz (R-Texas) will introduce acting Secretary of Homeland Security Chad Wolf at a Senate nomination hearing next week, with the aim of making Wolf's position permanent following reports that he has been illegally serving as acting secretary.
The House Committee on Oversight and Reform called for an investigation into "shocking allegations of medical atrocities" at the ICE detention center.
A total of 781 people have been arrested as a result of the Portland demonstrations, according to statistics gathered in a federal analysis.
"We don't have any authority to do that at the department," Chad Wolf said.
"I can appreciate if they would personally like to see different policies in place," the DHS's Ken Cuccinelli said.
The Government Accountability Office said Friday that the Department of Homeland Security had failed to follow the proper chain of succession, making Acting Secretary Chad Wolf's appointment to the position invalid.
In an interview with Newsweek, DHS Acting Seputy Secretary Ken Cuccinelli said believes racial injustice is a problem in the U.S., but that federal officers were right to crack down on "violent agitators."
Homeland Security Acting Deputy Secretary Ken Cuccinelli said the DHS would take "all necessary measures to ensure the safety of its officers and detainees."
"We have to isolate those individuals where we can do so safely," Mayor Ted Wheeler said. "We need to arrest them, and we need to hold them accountable."
The federal government has faced a series of lawsuits over its Portland deployment.
Between July 4 and 31, federal officers suffered a combined total of 277 injuries, DHS Acting Secretary Chad Wolf said.
Leaving the agency, Matthew Albence said, was "an exceptionally hard decision" to make.
The Department of Homeland Security has gone on a "shopping spree" over the past two months.
Portland protesters have accused the Trump administration of violating their rights.
"We will not be the people who sat by and watched our neighbors commit these atrocities," one protester said.
"DHS now says they have a limited number of agents in the area on standby to protect federal buildings," Seattle Mayor Jenny Durkan wrote.
DHS officials have said they refuse to pull federal law enforcement officers out of Portland, Oregon.
Oregon Senator Jeff Merkley said the use of federal police actions in Portland was "a gross violation of Americans' civil rights."
The DHS OIG issued the warning in a scathing report on CBP's acquisition capabilities to secure the southern border.
"We're not going to abdicate our mission," said DHS Acting Secretary Chad Wolf.
ICE has faced scrutiny over the program, which is expected to focus on its Enforcement and Removal Operations unit.
New York City lawmakers have approved a 2021 budget that will see $1 billion slashed from NYPD funding.
"We won't stand idly by while violent anarchists and rioters seek not only to vandalize and destroy the symbols of our nation," said DHS chief Chad Wolf.
Of the 1,045 admitted into the ICU, 546 are COVID-19 patients, the Arizona Department of Health Service's data indicated.
The FBI said this is an ongoing investigation, and an Oakland Police Department spokesperson said it is "unknown" if the killing was related to the unrest over George Floyd's death.
Chinese officials worked to conceal this effort by "denying there were export restrictions and obfuscating and delaying provision of its trade data," the DHS report alleges.
"Detainees who are elderly or who may otherwise be uniquely vulnerable to the worst effects of COVID-19 are of particular concern," read the Tuesday letter in part.
The COVID-19 outbreak has raised safety concerns for both asylum seekers and volunteers.