The Department of Homeland Security has requested additional troops for the U.S. border as a migrant caravan approaches and reports are that 800 personnel could be deployed.

The troops are likely going to be active duty but a final determination has not yet been made, nor on the exact number that will be sent, a U.S. official told NBC News. The troops are expected to be in place by the end of the month.

The news of 800 troops was first reported by CNN, based on several administration officials, and confirmed by the Associated Press.

Earlier Thursday, Trump tweeted that he was "bringing out the military" to stop people from crossing the southern border into the U.S. The president has referred to the border situation as a national emergency.

CNN reported an order authorizing the deployment could be signed as soon as Thursday.

The move comes 12 days ahead of the midterm election on Nov. 6 and as Trump has been escalating his immigration rhetoric at multiple campaign rallies each week. The president has said that immigration and border security is one of the most important issues of the campaign.

The troops will not be in riot gear, but will be behind the scenes providing logistical support to Customs and Border Protection officers, the official said. There are currently about 2,100 National Guard members working along the border to support border authorities. There will also be medical personnel sent to the border as well to provide support to CBP officers, the official said.

As of Wednesday, the caravan of several thousand from Honduras was in Huixtla, Mexico, more than 1,000 miles away from the U.S. border.

"Wait until you see what we do with the border (in the) next few weeks," Trump said Wednesday night at a campaign rally in Wisconsin. "Started the wall, have another $1.6 billion, want to build it, wait 'til you see what happens...You're gonna see a very secure border. The military is ready; they're all set."

The president's tweet Thursday morning referenced comments made by Brandon Judd, president of the National Border Patrol Council, on "Fox and Friends." Judd, a frequent guest on Fox News Channel, is the union representative for about 16,000 border patrol agents.

"Brandon Judd of the National Border Patrol Council is right when he says on @foxandfriends that the Democrat inspired laws make it tough for us to stop people at the Border," Trump tweeted.

Trump added, "MUST BE CHANDED, but I am bringing out the military for this National Emergency. They will be stopped!" he added, appearing to misspell "changed." Later, in another tweet, he advised "those in the Caravan" to "turnaround" because "we are not letting people into the United States illegally."

Brandon Judd of the National Border Patrol Council is right when he says on @foxandfriends that the Democrat inspired laws make it tough for us to stop people at the Border. MUST BE CHANDED, but I am bringing out the military for this National Emergency. They will be stopped! — Donald J. Trump (@realDonaldTrump) October 25, 2018

To those in the Caravan, turnaround, we are not letting people into the United States illegally. Go back to your Country and if you want, apply for citizenship like millions of others are doing! — Donald J. Trump (@realDonaldTrump) October 25, 2018

Trump has tweeted repeatedly in recent days about illegal immigration and the migrant caravan heading north through Mexico.

On Monday, Trump had tweeted, without evidence, that, "Criminals and unknown Middle Easterners are mixed in" in the caravan and that he had "alerted Border Patrol and Military that" it was a national emergency. Trump later admitted he had "no proof," to support the claim.