The United Nations human rights office on Friday called on U.S. security forces to limit their use of force against peaceful protesters and journalists, as clashes between federal agents and demonstrators continue in Portland, Ore.

“Peaceful demonstrations that have been taking place in cities in the U.S. such as Portland really must be able to continue without those participating in them and also the people reporting on them, the journalists, risking arbitrary arrest or detention, being subject to unnecessary disproportionate or discriminatory use of force or suffering other violations of their rights,” Liz Throssell, a spokeswoman for the U.N. human rights office, said at a news conference in Geneva, emphasizing that officers must be “properly and clearly identified.”

Anti-racism protests have rocked Portland for about two months, since a wave of demonstrations erupted across the United States in response to the killing of George Floyd, a black man who died in police custody in Minneapolis after a white officer knelt on his neck for nearly nine minutes. President Trump, eager to quell the unrest, deployed federal forces to Portland, sparking outrage among city officials who oppose the move.

Portland Mayor Ted Wheeler, who was among those tear-gassed by federal agents there this week, has called the officers Trump’s “personal army.”

But Trump has defended his decision to send federal forces to the city, claiming unrest in Portland is “worse than Afghanistan.” He has also said he would consider sending federal forces to other U.S. cities, including Chicago and New York.

Scenes from Portland in recent days, showing federal forces at times violently clashing with protesters, have provoked outcry across the nation.

Inspectors general from the Justice Department and the Department of Homeland Security said Thursday they would investigate federal agents’ conduct in Portland and Washington, D.C., where clashes occurred earlier this summer. And U.S. District Judge Michael H. Simon on Thursday barred officers “from arresting, threatening to arrest, or using physical force” against journalists or other legal observers without probable cause.

The U.N.'s concerns mirrored those of activists in the United States. “There have been reports that peaceful protesters have been detained by unidentified police officers and that is a worry because it may place those detained outside the protection of the law and may give rise to arbitrary detention and other human rights violations,” Throssell said.

Recent protests in the United States have sparked a global reckoning over racism and police violence.

In June, the U.N. Human Rights Council decried violent police tactics and called for an inquiry into systemic racism in the United States. The resolution came after an unusual debate on “systemic racism, police brutality and violence against peaceful protests” in the United States, requested by all 54 countries in Africa. It was adopted unanimously by the 47 countries that belong to the council.

“It is important to show Africa … the Human Rights Council has heard the plight of African and people of African descent calling for equal treatment and application of equal rights for all,” Dieudonné W. Désiré Sougouri, Burkina Faso’s ambassador to the United Nations, said when presenting the resolution.

The United States withdrew from the council in 2018.