WATCH: Trump signals additional troop increase along U.S.-Mexico border

President Donald Trump says the number of military troops deployed to the U.S.-Mexican border could go as high as 15,000.

Trump told reporters at the White House on Wednesday that “we’ll go up to anywhere between 10 and 15,000 military personnel on top of Border Patrol, ICE and everybody else at the border.”

He says the move would be aimed at preventing the entry of a caravan of migrants traveling from Central America. The caravan is still nearly 1,000 miles (1,600 kilometers) from the border.

Trump says that the U.S. was “going to be prepared” and that the migrants are “not coming into our country.”

Currently there are 2,100 National Guard helping at the border. The Pentagon says an additional 5,200 active-duty troops could join them.

Earlier in the day, Defense Secretary Jim Mattis pushed back on suggestions that the move to send thousands of active-duty troops to the Southwest border is a political stunt ahead of the midterm elections next week.

Mattis told reporters Wednesday at the Pentagon that the deployment of more than 5,200 troops is based on a request from the Department of Homeland Security. He says, “We don’t do stunts in this department.”

An estimated 4,000 Central American migrants in a caravan have been walking across Mexico toward the U.S. border. Mattis authorized the deployment of the active-duty troops, and 2,000 to 3,000 additional forces have been told to prepare to deploy if needed.

The forces are largely providing airlift transportation, tents, barriers and other logistical support for the Border Patrol.

The Associated Press wrote this story. The PBS NewsHour produced this video.