U.S. Immigration and Customs Enforcement says it has arrested a man this month who threatened to assassinate President Donald Trump.

According to ICE, Ramon Morales-Reyes, who illegally entered the U.S. from Mexico, sent a hand-written letter to the agency threatening to kill President Trump.

"I will self deport myself back to Mexico" after using a rifle "to shoot your precious president in [his] head," the letter reads.

Reyes was arrested May 22, the day after ICE received the letter. He is now in custody in a jail in Wisconsin while ICE prepares to remove him from the country.

"This threat comes not even a year after President Trump was shot in Butler, Pennsylvania and less than two weeks after former FBI Director Comey called for the President’s assassination," said Homeland Security Secretary Kristi Noem in a statement on the arrest. "All politicians and members of the media should take notice of these repeated attempts on President Trump’s life and tone down their rhetoric. I will continue to take all measures necessary to ensure the protection of President Trump."

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Noem was referencing a post by Comey that showed seashells arranged to form the numbers "86 47" — a combination some interpreted as a coded call for violence against President Trump.