Acting Defense Secretary Patrick Shanahan told reporters Friday the Pentagon stands ready to dispatch more troops to the border region if President Trump follows through with his pledge to increase the military presence along the U.S.-Mexico boundary.

Trump said after touring a section of recently upgraded border fencing in Calexico, Calif., last week, “We're going to bring up some more military” to deal with what he said were more than 70,000 illegal migrants rushing the border.

Shanahan said the Pentagon has had conversations with the Department of Homeland Security but has yet to receive a formal request.

“It shouldn't come as a surprise that we'll provide more support to the border,” he said in response to a reporter’s question as he prepared to meet with German Defense Minister Ursula von der Leyen. “Our support is very elastic, and given the deterioration there at the border, you would expect that we would provide more support.” Shanahan said he anticipates the support will be similar to what the military has already provided with several thousand troops, barrier construction, transport, and surveillance.

Shanahan will meet with a planning team at the Pentagon over the weekend to prepare for the potential request, he said.

“It will follow up with where are we on barrier construction, where do we stand on troops deployed, and then in the areas we anticipate, what type of preliminary plans should we be doing prior to receiving a request for assistance,” he said.

Democrats have been highly critical of the deployment of active-duty troops to the border, and many have cited a leaked internal memo the Marine Corps commandant sent to the Navy secretary warning that unexpected expenses, such as hurricane damage and border operations, could force him to cancel routine training and degrade combat readiness.

But in Senate testimony this week, Gen. Robert Neller insisted his memo was being misconstrued. “To say that going to the border was degrading our readiness is not an accurate statement,” Neller told the Senate Armed Services Committee Tuesday.

Neller’s March 18 memo listed eight categories of unfunded and unexpected expenses. Hurricane recovery was at the top of the list, but a number of expenses were included, such as the raise for civilian employees, which was not in the budget.

“We have a shortfall of just under $300 million, of which the border mission is less than 2 percent,” Neller said. “So my intent was to just simply lay out for my boss what these were and ask for support in trying to figure out how we might fund them.”

Pressed by Sen. Elizabeth Warren, D-Mass., Neller conceded some Marines, who are not doing the jobs they would normally do, could see a small degradation in their unit readiness, but he said it depended on the unit.

“Some of the units have gone down there and they've done tasks that are more in line with their core mission. Like engineer units or MP units. Aviation units that were assigned to that early on have actually improved their readiness because they are able to fly certain profiles and things,” he testified.

Neller reports to his civilian boss, Navy Secretary Richard V. Spencer, who requested the memo and jumped to Neller’s defense at the hearing.

“The main stress that we were dealing with at the time, senator, was the hurricane, which was imposing the greatest cost on the Marine Corps," Spencer told Warren. "Five hundred men for a month at the southern border is $1.25 million. In my mind, is that affecting my readiness stress? No, it's not.”

Neller said so far border operations have cost the Marine Corps $6.2 million.