The troop readiness in the U.S. military is at risk without a Senate-confirmed leader for the first time in history, Defense Secretary Lloyd Austin said Friday.

Speaking during a ceremony at Joint Base Myer-Henderson Hall, Austin said the Senate’s failure to confirm the services’ new leaders is disruptive to the force and could impact relationships with allies and partners around the globe.

The confirmation of the next Army chief and Marine commandant among more than 300 military nominations stalled by Alabama Sen. Tommy Tuberville, a Republican, over the Pentagon’s policy to pay for travel when a service member has to go out of state to get an abortion or other reproductive care.

"Today, for the first time in the history of the Department of Defense, two of our services will be operating without Senate-confirmed leadership," said Austin. "Great teams need great leaders, and that’s central to maintaining the full might of the most lethal fighting force on earth."

Army Gen. James McConville is retiring and has been nominated to become the next service chief. On Friday, George became the acting chief. Similarly, Marine Gen. Eric Smith has been nominated to be the next commandant but is serving in an acting capacity now because he hasn’t been confirmed.

Both can serve as "acting" chiefs but can do nothing that would presume confirmation. As a result, they can’t move into the main residences or offices or issue formal planning guidance, which is traditional for a new leader. And officials have also warned that there are some authorities, including some budgeting powers, that don’t shift to acting leaders.

"We need these leaders in place to ensure the readiness of our force," said Army Secretary Christine Wormuth, speaking at the ceremony. "And we need to end all this uncertainty for our military families." She noted that officers and their families are in limbo, waiting to see if they will move or not to new bases, states and jobs.

Smith addressed the issue in a letter to the force on Thursday, laying out the need for the Corps to continue modernization efforts and broader programs to improve warfighting.

"Until the Senate confirms our 39th Commandant, this guidance will serve as our reference point," Smith said. "I cannot predict how long this process may take, but waiting is not an option for Marines, so we will move out as a team – just as we would in combat."

Tuberville has blocked efforts to have Senate votes on all nominations because he disagrees with the travel pay policy. And congress is now out on summer vacation, which means there will be no action on the jobs for weeks.

Adm. Michael Gilday, chief of naval operations, will step down on Monday. Adm. Lisa M. Franchetti, the current vice chief, has been nominated to take over.

Further complicating things, Air Force Gen. CQ Brown has been nominated to become the next chairman of the Joint Chiefs of Staff when Army Gen. Mark Milley leaves, as required by law, on Sept. 30. The current vice chairman, Adm. Christopher Grady, would serve as acting chairman.

Brown, whose term as Air Force chief goes for another year, will remain in that post. Gen. David Allvin has been nominated as the next Air Force chief if Brown moves to the chairman’s job.