Washington (CNN) While President Donald Trump has been relatively silent on the threat posed by what he had termed an "invasion" of migrants heading toward the southern border prior to the midterm elections, Defense Secretary James Mattis traveled to Texas on Wednesday with a simple message for US troops deployed to the area: Ignore the news and focus on the mission at hand.

He also made it clear that their mission will not involve fending off a hoard of dangerous migrants as Trump insisted in his pre-election rhetoric.

Accompanied by Secretary of Homeland Security Kirstjen Nielsen, Mattis appeared to take the lead when addressing troops at Donna Base Camp, using the opportunity to encourage those present to block out any outside noise related to politics, and he emphasized the importance of serving as "confidence builders" for Border Patrol officers.

"Now, there's all sorts of stuff in the news, and that sort of thing. You just concentrate on what your company commander, your battalion commander tells you. Because if you read all that stuff, you know, you'll go nuts," Mattis said. "You know what your mission is here. You've had to deploy on short notice to a nontraditional location and do your jobs. So you focus on doing that."

"We were asked by the secretary, due to the number of people coming this way, to back them up. What does that mean? It means that her people do all the work, but we're standing behind them as a confidence builder," he added, referring to the request from the Department of Homeland Security to provide support.

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