Acting Pentagon chief not decided yet on funding border wall

The remarks come one day after Trump declared a national emergency to bypass congressional approval and secure funding for the construction of his controversial wall on the US-Mexico border.

Trump said Friday that the declaration, which can help him use certain Department of Defense funding to build the wall, would be necessary to deal with what he described as a crisis of illegal immigration.

However, the law stipulates that the defense secretary has to decide whether the wall is militarily necessary before money from the military construction budget can be allocated for it.

Shanahan on Saturday said he had not determined if such a wall was a military necessity or how much the Pentagon should spend on the wall.

“We always anticipated that this would create a lot of attention and since moneys potentially could be redirected, you can imagine the concern this generates,” Shanahan told reporters traveling back with him from his trip to Afghanistan, the Middle East and Europe.

“Very deliberately, we have not made any decisions, we have identified the steps we would take to make those decisions.”

He went on to say that military planners had conducted an initial analysis and that he would begin reviewing it on Sunday.

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

Trump needs $5.7 billion for his promised wall, but lawmakers have appropriated just $1.375 billion for barriers, not a solid concrete wall.

His decision to declare a national emergency has also been hit with the first lawsuit, in what is expected to become a lengthy legal face-off between the Republican head of state and his opponents over the barrier.

Liberal advocacy group Public Citizen filed the lawsuit on behalf of the Frontera Audubon Society and three landowners in South Texas who had been informed that their land would be used to build the wall.