An undocumented US immigrant has been arrested after he sent a handwritten letter to the government saying he planned to assassinate President Donald Trump, officials said.

The man, 54-year-old Ramon Morales-Reyes, said in the letter he would ?shoot your precious president in is [sic] head? before self-deporting back to his native country of Mexico.

He is now in Immigration and Customs Enforcement (Ice) detention in Wisconsin with deportation proceedings pending, the Department of Homeland Security (DHS) said.

Mr. Morales-Reyes had a criminal record including multiple arrests and attempts to enter the US illegally, the DHS said. The BBC couldn?t find a lawyer for Mr. Morales-Reyes to comment.

?Thanks to our ICE officers, this illegal alien who threatened to assassinate President Trump is behind bars,? DHS Secretary Kristi Noem said in a statement.

Homeland security officials said authorities received the letter from Mr. Morales-Reyes on 21 May.

They included a copy of the letter in a press release. Written in blue ink on lined-paper, the letter said: ?We are tired of this president messing with us Mexicans.?

?You have been deporting my family and I think it is time Donald J. Trump gets what he has coming to him.?

The final line of the letter said: ?I will see him at one of his big rallies.?

Mr. Morales-Reyes was arrested a day after the letter was received. According to officials, he had attempted to enter the US illegally nine times between 1998 and 2005, and had been arrested for a felony hit and run.

After vowing to use the US military to carry out mass deportations during his election campaign, Trump?s administration has aggressively pursued undocumented migrants.

Mr. Morales-Reyes? mention of self-deporting in his letter appears to be a reference to a DHS announcement of $1,000 (?751) bonuses and paid travel for people who leave the US voluntarily.

Some of Trump?s methods, including using the 18th Century Alien Enemies Act to deport Venezuelan migrants his administration accuses of gang activity, have been blocked by the courts.

He's also called for an additional 20,000 DHS officers to enforce his deportation policies.

In her statement, Noem noted that this latest threat against President Trump comes less than a year after a gunman attempted to assassinate him at a rally in Butler, Pennsylvania.

She also referenced a recent social media post by former FBI Director James Comey in which he posted images of sea shells on a beach spelling ?8-6-4-7?. The message was interpreted by some as a call to assassinate Trump, the 47th president. Comey denied the allegations and took down the post.

?All politicians and members of the media should take notice of these repeated attempts on President Trump?s life and tone down their rhetoric,? Noem said. (BBC)

Update news