The Pentagon has approved President Trump's request for additional military personnel to be deployed to the border as a caravan of people coming from Central America heads north.

The Department of Homeland Security and the Department of Defense issued a joint announcement Friday in response to a request from the secretary of Homeland Security.

The additional personnel will supplement the 2,100 National Guard troops already deployed to Texas, New Mexico, Arizona, and California. Trump asked for the Guard's help in March when a 1,000-person caravan coming from Central America was reported.

[New: Trump sending 5,200 active duty troops to the border]

The Defense Department will provide manpower to help with tasks such as assistance with planning; helping engineer temporary barriers, barricades, and fencing; helping move border patrol personnel by air; medical teams to triage, treat and prepare patients for transportation on commercial services; command and control facilities; temporary housing for border patrol; and personal protective equipment for border patrol.

The Pentagon has asked its component, the United States Northern Command, to oversee the operation.

The details regarding this new deployment remain unclear, but that's because the Pentagon has yet to decide who it will send to the border.

When DHS makes a request to DOD for additional support, the Pentagon will either approve or deny that initial request. Then, in the following days, defense officials will decide how to fulfill Homeland Security's needs.

Trump had told military officials in a meeting earlier this week he wanted active-duty troops in addition to the guard. DOD would not comment on whether he will get personnel from both groups.

Defense Secretary Jim Mattis was reported Thursday as expected to dispatch 800 active-duty troops to the border.