The Trump administration is expected to extend the military mission along the U.S. border with Mexico, a White House official said Wednesday, likely keeping troops away from their normal posts through the holidays.

The official, speaking on the condition of anonymity to discuss plans that have not yet been announced, said the assignment was expected to last at least 45 days beyond its scheduled end date of Dec. 15.

That decision would affect almost 6,000 active duty military personnel now stationed in southern areas of Texas, Arizona and California, lengthening a mission critics have described as an unnecessary ploy to galvanize anti-immigrant sentiment.

News of a possible extension, which was first reported by NPR, comes days after a dramatic confrontation at a border crossing outside San Diego.