US Customs chief refusing to say whether Trump consulted him about deploying military to guard the border
President Donald Trump touring border wall prototypes in San Diego with then-acting Commissioner Kevin McAleenan. CBP photo by Ralph Desio.

President Donald Trump's head of U.S. Customs and Border Protection refused to say when he learned of the White House's controversial plan to send military troops to the southern border, ABC News reported Saturday.

The Pentagon was reportedly caught off guard by Trump's announcement of deploy National Guard troops to guard the shared border with Mexico.

In an interview, commissioner Kevin McAleenan was asked when he first learned of Trump's plan.

"I'm not going to comment on the timing of internal administration discussions with that level of specificity," he said.

The plan to use troops came after both Mexico and Congress refused to pay for Trump's promised wall.

McAleenan was acting director from the start of Trump's term until he was finally confirmed by the Senate 18 days ago.

"We need a lot more capability to see what’s happening and crossing that border," McAleenan added. "National guard extends that capability significantly."