The Department of Homeland Security has authorized its personnel to collect information on protesters who threaten to damage or destroy public memorials and statues, regardless of whether they are on federal property, a significant expansion of authorities that have historically been used to protect landmarks from terrorist attacks.

The new guidance was issued as department personnel have been dispatched to police and detain people protesting police violence, itself an untraditional role for a department set up to secure borders and transportation systems.

The guidance, obtained by The Washington Post, is described as a “job aid” for personnel implementing an executive order that President Trump signed last month, targeting protesters who threatened to remove statues honoring Confederate officers and other people they consider racist.

The document refers to apparently ongoing intelligence activities, directing the guidance to “personnel collecting and reporting on various activities in the context of elevated threats targeting monuments, memorials, and statues.”

The guidance, first reported by the blog Lawfare, appears to authorize monitoring of social media posts as well as the use of public information sources to keep tabs on individuals or groups the department says may “damage or destroy any public monument, memorial, or statue.”

The document makes no distinction as to types of monuments and doesn’t state that they must be located on federal property. Personnel are told that they must be able to articulate why someone is a threat and cannot rely on “ ‘hunches’ and intuitions, which are insufficient.”

The document is unclassified and was issued by the department’s Office of Intelligence and Analysis. DHS didn’t respond to a phone call and email requesting comment.

Since its inception, DHS has played a limited role in protecting revered American symbols such as the Gateway Arch in St. Louis and the Statue of Liberty and always acts against terrorist attacks, not protests by American citizens, said Paul Rosenzweig, a senior policy official at the department during the George W. Bush administration.

The new guidance is “a complete misapplication of existing authorities to benefit the president,” said Rosenzweig, now a senior fellow at R Street, a think tank. “Trump is morphing DHS into his private little rogue, secret army.”

The administration’s deployment of DHS forces to police demonstrations and detain protesters in Portland, Ore., has drawn strong condemnation from officials in the state. Trump has portrayed the protesters as lawless radicals intent on damaging and destroying property.

Nothing in the intelligence document directs or allows the department to detain protesters. But it does say that DHS may collect information about “individuals or groups,” as well as their “tactics, techniques, or procedures” and refers to existing rules on what information can be collected.

The existing rules do allow the department to use the “least intrusive means” to collect information about U.S. citizens, specifically “physical surveillance, the use of mail covers, and the use of monitoring devices,” which cannot be hidden and may include public information sources. Mail covers allow the government to record information on the outside of an envelope or parcel before it’s delivered.

Some of those collection rules are limited to U.S. citizens believed “to be engaged in or preparing for espionage, other intelligence activities, sabotage, or assassination on behalf of a foreign power, organization, or person.” It’s not clear from the new guidance how that applies to Americans protesting monuments or peacefully exercising their rights to free speech and assembly.

The department is not authorized to conduct electronic surveillance such as wiretapping. But it can ask other federal agencies to do so, Rosenzweig said, principally the FBI.

The document explicitly prohibits any intelligence activities “for the sole purpose of monitoring activities protected by the First Amendment” or for deterring free speech. It also spells out guidance for collecting information about threats of violence to law enforcement and other government personnel and facilities.

Any information the department collects on U.S. citizens must be discarded after 180 days if it doesn’t further another appropriate government mission. But the information can be shared with a broad range of other groups, including within the federal government, as well as state and local organizations and private-sector groups engaged in law enforcement, counterterrorism and homeland security operations, the document states.