The U.S. Air Force no longer plans another round of layoffs in fiscal 2015, the service's top civilian said.

Air Force Secretary Deborah Lee James made the announcement on Tuesday during an online discussion with troops, marking a shift in personnel policy for the service, which had planned on involuntarily separating more airmen to further downsize the active-duty force.

"Enough is enough," she said. "Contrary to what we said earlier -- that there would still be involuntary force shaping in FY15 -- we have now determined we will not do involuntary force shaping in FY15." James added, "We have reduced far enough. We will not go lower. We will fight to hold on to the numbers that we now have."

The Air Force has about 315,000 officers and enlisted members on active duty, according to Pentagon personnel statistics dated Oct. 31. That's the lowest level since the service was created in 1947. What's more, it's slated to fall even further, to 310,900 airmen by the Sept. 30 end of the current fiscal year due in part to automatic budget cuts known as sequestration.

"We are the smallest Air Force that we have ever been in our history," James said.

The secretary said the statistic is all the more astonishing given the increased pace of operations in such places as the Middle East, where U.S. warplanes are helping to launch airstrikes against militants affiliated with the Islamic State in Iraq and Syria, or ISIS, and in Africa, where American cargo planes are delivering troops and supplies to help combat the Ebola outbreak.

"We have fewer people. We have fewer aircraft. The aircraft that we have air getting older and older. And at the same time all of this is happening, our ops-tempo has gone through the roof," James said.

The Air Force reduced its end-strength in part by cutting more than 6,000 airmen involuntarily over the past year, including more than 5,000 enlisted members and more than 1,000 officers. That's in addition to the 13,000 airmen let go under voluntary separation programs.

While she didn't say what sorts of incentives, such as 15-year retirements or voluntary separation pay, may be used next year, James did say the service will continue to award bonuses to retain airmen with critical skills.

The secretary also acknowledged the need for the service to do more to retrain airmen interested in pursuing in-demand career fields, such as intelligence, surveillance and reconnaissance, or ISR; cybersecurity; and nuclear security.

"It's been a force-shaping situation where we have tried to reduce certain [Air Force Specialty Codes], where we determined we had too many, and beef up others where we had too few," she said. "There was a certain amount of cross training that went on but not as much as some of us would have liked to have seen, perhaps, and we need to do a better job of that in the future."

Overall, the Defense Department in its fiscal 2015 budget requested funding for an active-duty military of 1.31 million troops, a decrease of nearly 37,000 service members from the previous year, according to budget documents. The manpower reductions were designed in part to curb personnel costs.

-- Brendan McGarry can be reached at Brendan.McGarry@military.com