WASHINGTON — Lead U.S. Navy and Marine Corps officials on Tuesday downplayed concerns that troop deployments to the southern border are hurting military readiness, following a memo from the Marine commandant warning that the deployments are causing problems.

Navy Secretary Richard Spencer and the author of the memo, Marine Commandant Gen. Robert Neller, told lawmakers there has been no negative impact on troop readiness and that the financial costs have been minimal. Neller emphasized the deployments were one small strain on budgets among eight others he’d outlined, including hurricane damage at Marine Corps Base Camp Lejeune, North Carolina.

“I personally checked the readiness of every unit [on the border], and with only one exception there was no impact on their actual readiness,” Neller said in an exchange with Sen. Jeanne Shaheen, D-N.H. “In fact a couple of units improved their readiness. So to say going to the border was degrading our readiness was not an accurate statement.”

The comments to the Senate Armed Services Committee came as Shaheen, Sen. Elizabeth Warren, D-Mass., and other panel Democrats wrote to Pentagon leadership, asking for an explanation regarding the disparity between military officials who have said readiness impacts were minimal and the memo from Neller to Spencer last month warning that training exercises could be canceled.

On Tuesday, Neller said he had crafted the memo to describe risks to readiness in support of Spencer’s request to Congress to reprogram funding. And in an exchange with Warren, Neller added that training exercises had been at risk, but none were delayed or canceled.

The Marine Corps faced $300 million in unfunded expenses — including $6.2 million for the border mission — that could have required the cancellation of exercises, “which could eventually effect the readiness of the force,” Neller explained.

Neller did acknowledge “a small number” of troops were diverted from one exercise because they were participating in the border mission. While some military police and aviation units have improved their readiness, Neller said there is one unit on the border that would risk its readiness if it stays beyond 60 days.

Spencer told Warren he asked for the memo to identify financial stresses. The main stress turned out to be the cost of hurricane damage, he added.

“This was item G on a whole list,” Spencer said of the border mission. "Five hundred men for a month on the southern border is $1.25 million. In my mind, is that affecting my readiness stress? No, it is not.”

The Marine Corps has said it sustained about $3.5 billion in damage at Camp Lejeune as well as surrounding facilities in North Carolina from hurricanes Michael and Florence. However, Neller said last week through Twitter that Congress will approve a request to reprogram $400 million to address the damage.

The calls for emergency funding come amid debate between the Trump administration and Congress over the White House’s proposal, enabled by the president’s emergency declaration, to repurpose billions of dollars in military construction money to help extend a wall at the U.S.-Mexico border.

While Democrats generally have questioned the U.S. military presence along the southern border, some Republican lawmakers and Pentagon officials have said the deployments are not improper or even unusual, noting that past presidential administrations have sent troops to assist border patrol agents.

The Pentagon has acknowledged more than 5,000 military personnel have been deployed to the southern border. The Pentagon spent $235 million on troops there in fiscal 2018, and it estimates it will spend $448 million in fiscal 2019.