The Army is dangerously undermanned and is operating at "high military risk," the service's top general said Thursday. The U.S. would need about 200,000 more soldiers to operate with only significant or moderate risk, he told senators.

Tight budgets, however, make that increase impossible and leave soldiers at greater risk if they are called to the battlefield.

Gen. Mark Milley, the Army chief of staff, told the Senate Armed Services Committee that the military is operating "at this current state at high military risk."

Sen. Joe Manchin, D-W.V., asked what it would take to change that after hearing frontline generals tell him there's "no way" to meet current threats to the country with only 980,000 active-duty, reserve and National Guard soldiers, the number to which the Army is drawing down.

"What would it take for us not to be at high risk?" Manchin asked. "These are artificial caps and all the other bullcrap we're dealing with."

Milley responded that the service would need about 1.2 million personnel to reduce the risk to "significant" or "moderate."

"So we're over 200,000 troops short?" Manchin asked.

"Right. And at a billion for every 10,000 soldiers, that money's not there, so we are going to make the most efficient and effective use of the Army that we have," Milley said.

The general, however, stressed that it's not just the size of the Army that puts it at risk. It's also the readiness, training and technology capability of those troops.

"It's the sum total of all of those things. We tend to laser-focus on size. I think that is critical, capacity, size, I think that's fundamental to the whole piece. But there are other numbers to calculate beyond the number of troops," Milley said.