This article is more than 1 year old

This article is more than 1 year old

Donald Trump has authorized US troops guarding the border against migrant caravans to use deadly force if necessary, it was reported on Wednesday.

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A White House “decision memorandum”, signed by the president and published by Newsweek, warns that “credible evidence and intelligence” indicates thousands of approaching Central American migrants “may prompt incidents of violence and disorder” that could threaten border patrol agents and other government personnel.

It expands the authority of US troops to include “a show or use of force (including lethal force, where necessary), crowd control, temporary detention and cursory search” to protect the border agents.

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The memo comes amid ongoing controversy over the costly deployment of around 5,900 active-duty troops to the south-west border, announced by Trump eight days before the midterm elections during a period in which the president was seeking to inject fears over immigration into the campaign.

The Military Times first reported on Wednesday that John Kelly, the White House chief of staff, had signed an order that broadened the troops’ authority to include lethal force. Newsweek confirmed this and published it along with the memo from Trump himself.

Speaking to reporters, the defense secretary, Jim Mattis, acknowledged that the troops can use lethal force but said he would only exercise such authority after receiving a specific request from the Department of Homeland Security (DHS).

“There has been no call for any lethal force from DHS,” Mattis insisted, according to the Task & Purpose website. “There is no armed element going in. I will determine it, based on what DHS asks for and a mission analysis.”

Asked how the military would avoid a repeat of a 1997 incident in which marines on the border mistakenly shot a teenager, the secretary replied: “I’m not going to dignify that. They’re not even carrying guns, for Christ’s sake.”

Earlier this week the New York Times reported that, according to an internal Homeland Security Department document, the probability that US border guards will face violence at the southwestern border is “minimal”.

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Mattis also confirmed that the White House order gives the troops authority to temporarily detain immigrants in the event of disorder or violence against border agents. Such detention would be measured in “minutes, not even hours”, he said, and does not mean troops would be carrying out arrests or performing law enforcement, which would violate a law dating back to 1878.

The military deployment to the south-west border will cost an estimated $210m, according to a Pentagon report to Congress obtained by the Associated Press. This includes $72m for the 5,900 active-duty troops plus $13m so far for 2,100 national guard troops who have been performing a separate border mission since April.

Democrats including Senator Elizabeth Warren and Congressman Beto O’Rourke have written to Mattis requesting information about Trump’s decision to deploy the troops. They highlighted a New York Times report that indicated that Pentagon officials view the deployment as “an expensive waste of time and resources, and a morale killer to boot”.