Washington(CNN) Acting Defense Secretary Patrick Shanahan was grilled by Senate lawmakers Thursday about President Donald Trump's plan to declare a national emergency and use $3.6 billion in military funding to build a wall along the southern US border.
While testifying before the Senate Armed Services Committee, Shanahan said that "military construction on the border will not come at the expense of our people, our readiness or our modernization."
But that did little to reassure some senators, who pressed the acting secretary for details about whether the Department of Defense will cancel certain military construction projects that have already been authorized in order to free up money for the wall.
Shanahan told the committee's top Democrat, Sen. Jack Reed of Rhode Island, that he does not yet have a final list of projects that could lose funding as a result of the administration's plan.
That drew a critical response from independent Angus King of Maine, who said he found it "hard to believe" that the Pentagon does not yet know which projects will be impacted.
"You've had a month," he said.
Later in the hearing, King pressed Shanahan and Under Secretary of Defense David Norquist to explain where the money will come from.
"The $3.6 (billion) is coming from somewhere, and it's coming from projects that were authorized and appropriated by this Congress, and you won't tell me what they are," King told the panel of Pentagon officials.
Norquist told King the funding "would in fact come from projects previously authorized and appropriated from Congress" but said those dealing with family housing or military construction will not be touched.
King then turned his attention to Shanahan, asking if he had spoken to any senators "to assure them that projects in their state are not going to be affected by this policy."
"No, I have not, Senator," Shanahan responded.
But Republican Sen. Martha McSally of Arizona seemed to then contradict Trump's acting defense secretary, recalling a conversation where they discussed four projects in her home state that have already been appropriated for the 2019 fiscal year.
Shanahan confirmed that he and McSally had previously discussed the issue.
The Senate passed a resolution Thursday to block Trump's emergency declaration but the President tweeted shortly after the vote making it clear he plans to veto the measure.
Shanahan and Joint Chiefs of Staff Chairman Gen. Joseph Dunford told lawmakers that they agree the situation on the southern border is not a "military threat."