FILE PHOTO: U.S. Marines deploy concertina wire at the U.S. Mexico border in preparation for the arrival of a caravan of migrants at the San Ysidro border crossing in San Diego, California, U.S. November 15, 2018. REUTERS/Mike Blake

WASHINGTON (Reuters) - U.S. Defense Secretary Jim Mattis has approved a request to extend the deployment of troops to the U.S. border with Mexico until the end of January, a U.S. official said on Tuesday, a move that had been largely expected.

The U.S. official, speaking on the condition of anonymity, said the support would include “limited aviation, engineering, medical, and military police capabilities.” The current authorization was set to expire on Dec. 15.