The head of the US Department of Homeland Security has ordered his agency to stop collecting information on American journalists covering protests in Portland, Oregon, after a media report on the practice, a spokesman said.

The Washington Post on Thursday reported that the department compiled “intelligence reports” on journalists using a government system meant to share information about suspected terrorists and violent actors.

Upon learning of the practice, Department of Homeland Security (DHS) Acting Secretary Chad Wolf directed the agency's Intelligence and Analysis Directorate to stop collecting information involving members of the press, a DHS spokesman said late on Thursday.

“In no way does the acting secretary condone this practice and he has immediately ordered an inquiry into the matter,” the spokesman said in a statement.

The intelligence unit shared intelligence reports on journalists from the New York Times and the blog Lawfare, noting they had published leaked unclassified documents about DHS operations in Portland, the newspaper reported.

Wolf's order came as Portland had its first night in weeks without tear gas after state police took over from federal agents guarding a courthouse that has been the focal point of violence between protesters and officers.

The agents withdrew under a deal between Oregon's governor and US officials to end a deployment which sparked a stand-off between Republican President Donald Trump and Democratic mayors over the use of federal force in their cities.

A few hundred people demonstrated outside the federal courthouse until around 2am when they left of their own accord, according to a Reuters reporter.

Trump sent federal tactical police to confront what he called a “beehive of terrorists” who have set fires and broken windows at the courthouse since late May when protests against police violence began following the death of George Floyd in Minneapolis.

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Democratic mayors said the deployment escalated tensions and was political theater for Trump's “law and order” campaign ahead of the November 3 election.