Acting Defense Secretary Patrick Shanahan said late Saturday he has not reviewed President Trump's proposed use of military funds to build a border wall — and that he's unprepared to vouch for White House claims to have steered billions of dollars toward the project.

"There's been no determinations by me," Shanahan told reporters. "That's what I'll be doing tomorrow. I just want to make a point of this. We are following the law, using the rules, and we're not bending the rules, OK?"

Trump declared a national emergency Friday to fund a Mexico border wall after Democrats in Congress provided just $1.375 billion for fencing along a 55-miles stretch of land, much less than the $5.7 billion Trump sought for 234 miles of wall.

The White House said the emergency declaration was needed only to redirect $3.6 billion in military construction funds, and that Trump would redirec, without emergency powers, about $600 million from the Treasury Department's forfeiture fund and about $2.5 billion from Defense Department anti-drug activities.

Shanahan said the military has for weeks been performing an analysis of the border in anticipation of a possible emergency declaration and that he intends to review the results soon.

"I will go in and review that analysis now that the emergency has been declared. Based on that, we can do an assessment of what would be appropriate," he said.

"We haven't delineated what projects we would go do," he said. "Very deliberately, we have not made any decisions. We've identified the steps we would take to make those decisions. This is the important part of that. We laid that out so we could do it quickly. We don't want to fumble through this process."

Shanahan, who assumed his role last month after former Defense Secretary Jim Mattis resigned in protest, was careful not to contradict Trump.

"I think you can trust the numbers in terms of the potential. Then you've got to marry it up with, you know, where the money would be spent," Shanahan said.