Federal agents disperse Black Lives Matter protesters near the Mark O Hatfield United States Courthouse on July 20, 2020 in Portland, US. (PHOTO / AP)

WASHINGTON - Mayors of several US cities including Portland and Chicago signed a letter on Monday, urging the federal government to immediately withdraw its forces and halt their "unilateral deployment" to cities.

In the letter published on Twitter, Ted Wheeler, mayor of Portland, northwestern state of Oregon, along with his five counterparts in Chicago, Seattle, Atlanta, Washington, DC and Kansas City, said unilateral federal intervention is unacceptable and "violates fundamental constitutional protections and tenets of federalism.”

In Portland, their actions have escalated events and increased the risk of violence against both civilians and local law enforcement officer.

Ted Wheeler, Mayor of Portland

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"In Portland, their actions have escalated events and increased the risk of violence against both civilians and local law enforcement officers," the mayor said, listing the troops' violent acts, including shootings, against peaceful protests in the city.

The death of African American George Floyd in May has sparked nationwide protests, and Portland has witnessed nightly demonstrations against police brutality and systemic racism.

In June, US President Donald Trump signed an executive order to protect monuments and statues from protests as well as combat criminal activities.

In response, the Department of Homeland Security sent federal law enforcement officers to Portland to help the city restore order. However, the role played by the federal troops stationed in the city was largely questioned and criticized.

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As the United States is facing unprecedented challenges such as the raging COVID-19 pandemic, economic devastation and civil rights movement, mayors "need help of our federal government" instead of irresponsible actions that threaten safety and progress in the society, the letter added.

In a CNN broadcast on Sunday, Wheeler repeated his call for the federal troops to leave. "They're not wanted here. We haven't asked them here. In fact, we want them to leave," he said.