WASHINGTON — Army Chief of Staff Gen. Mark Milley said he would use additional troops mandated by Congress to fill out undermanned tactical units.

"Manning has been the biggest of the problems dragging readiness back, preventing us from making leaps and bounds and improvements in readiness," Milley said at an Association of the US Army breakfast in Arlington, Virginia, on Thursday.

"If we get additional troops," he said, "we would prioritize the operational force in the tactical units within there in order to make them healthy."

Like last year, Milley said his priority this year is readiness. In recent years with shrinking budgets, modernization has taken a back seat so the Army can sustain operating at high-readiness levels.

And maintaining readiness isn't easy because the Army is stretched thin and deployments are only increasing.

Milley said the first tranche of tanks belonging to the 3rd Brigade of the 4th Division out of Fort Carson, Colorado, are arriving in Bremerhaven, Germany, marking the start of the deployment of the first heel-to-toe rotational heavy armored brigade combat team as part of the US military buildup in the region to reassure allies and deter against an aggressive Russia.

And in the Middle East, for the first time since the Korean War, the Army has simultaneously deployed two National Guard divisions — the 36th and the 29th.

The Army also has 28,500 troops in South Korea alone with others deployed in Japan as well as offshore, Milley said. The service continues to rotate a brigade through South Korea at a very high level of readiness to help defend South Korea against North Korea's ever-increasing missile launches.

"Readiness is not just training, manning and equipping back here," Milley said, but "part is strategic deployment, rotations through contingency or training events overseas. We have made significant strides but we are not there yet. We are not at the level of readiness that we need to fully execute the national strategic plans to the level that I would be comfortable with."

Milley cautioned that the troop increase must come with money because if it doesn’t it would create a "hollow force" — meaning less would be invested per soldier, driving down capability and readiness.

The Army is now congressionally mandated to bring its end strength to 476,000 by Oct. 1. The Army was planning for a drawdown to 475,000 by the end of fiscal 2016, a further decrease to 460,000 soldiers in 2017 and a final decrease to 450,000 in 2018.

Improving manning levels will be a top priority within readiness, Milley said, because existing formations are "understrength." The chief said the Army sets a target of 90 to 95 percent manning levels depending on the unit, but when 10 percent is unavailable or you take others out of the mix due to day-to-day activities, that strips troops from their training.

"You find units going into training sometimes are down to 80 percent or in some cases even lower, which is not good for readiness," he said.

While it is thought the Trump administration could mean bigger defense budgets in the future, Milley was cautious to discuss what he’d like to do with extra money should he have it.

The chief said he’s operating off a priority list that is based on the current president’s budget, but he indicated it would be poor planning if he didn’t have a priority list designed around a possibly larger budget.

"I have developed a priorities list, which has not been publicly disseminated," Milley said, and when the time comes spend from that list, he added, it will be shared with civilian leadership, the Department of the Army and Capitol Hill.

While the first priority will remain readiness, Milley did highlight some modernization priorities the Army will need to focus on in the coming years.

Air defense is an area with a capability gap, Milley said, but "we know what is out there and we want to work on that."

Ground mobility is another big area where the Army has introduced some programs, particularly one focused on providing better capabilities to the light infantry force.

"Aviation is very vulnerable against a near-peer, high-end threat," Milley said. So the Army is focused on protecting aircraft and extending their range, among other efforts.

The Army is looking at nontraditional kinetics like lasers, which is farther afield, and extending the range of munitions. And the service is heavily focused on fighting near-peer adversaries with capabilities — such as electronic warfare and position, navigation and timing in a GPS-denied environment — that give US forces freedom of action in the electromagnetic spectrum.

Jen Judson is an award-winning journalist covering land warfare for Defense News. She has also worked for Politico and Inside Defense. She holds a Master of Science degree in journalism from Boston University and a Bachelor of Arts degree from Kenyon College.

More In Land