The Air Force is the smallest it's ever been, but it may have to cut 10,000 more airmen if budget cuts return, an Air Force two-star said.

Air Force Secretary Deborah Lee James has said "enough is enough" when it comes to downsizing, and the Air Force's proposed fiscal 2016 budget calls for increasing end strength by 4,020 active-duty airmen and 2,600 reserve forces airmen.

But the budget does not include the steep spending cuts known as sequestration, which went into effect in 2013 after Congress and the president failed to reach an agreement on taxes and spending. While lawmakers have provided temporary relief to the budget cuts, sequestration will return with a vengeance next fiscal year unless Congress takes action.

If Congress does not give the military all the money it is asking for, the Air Force will have to cut $10 billion from its budget in one year, and that means that instead of rising to about 492,000, overall, end strength would shrink to about 482,000, with personnel cuts across the active-duty and reserve forces, according to the Air Force's budget presentation.

Current total force end strength is about 485,000 — 313,000 active-duty airmen, 67,000 Air Force Reserve airmen and 105,000 airmen in the Air National Guard.

"Further reductions would leave us with a team that has an incomplete roster, that is too small to meet a demanding schedule, and allows little time to practice and provides no down time," said Maj. Gen. James Martin, Air Force deputy assistant secretary for budget. "Our airmen deserve better than that."

Overall, the Defense Department's proposed base budget for fiscal 2016 is about $38 billion higher than the mandated level imposed by Congress in the 2011 Budget Control Act .

Martin emphasized that cutting 10,000 airmen is "one potential action," and the Air Force would work with Congress and the Defense Department to look at other options to save money.

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"Before we made any final decisions, we'd have to know what the actual BCA [Budget Control Act] funding levels were," Martin said on Monday. "Then we would go back and we'd look across all five core mission sets and make sure that we're meeting the most urgent requirements that — that are expected out of the Air Force."

Chief of Staff Gen. Mark Welsh has said that he and James do not believe the Air Force can reduce any more personnel.

"We are getting too small to succeed, as opposed to too big to fail," Welsh said at a Jan. 15 news briefing. "So we're at a point now where we are undermanned in many career fields because we've taken people out of them to put in other areas to shore up those areas."

Still, cutting 10,000 airmen shows how drastically the Air Force would have to slash its budget under the lower spending levels imposed by Congress, said Air Force spokeswoman Maj. Melissa Milner.

"Additional reductions would cripple the Air Force's ability to accomplish our five core missions," Milner said Wednesday in an email to Air Force Times. "However, since sequestration would shrink Air Force funding to levels that impact our ability to sustain readiness, the Air Force would be forced to consider all options to balance readiness, modernization and personnel accounts while simultaneously fulfilling combatant commander requirements."

Congress has put the Air Force in a "very, very tight box" with few alternatives to cutting airmen to save money, Mark Gunzinger, of the Center for Strategic and Budgetary Assessments, told Air Force Times on Thursday.

Lawmakers have blocked the Defense Department's request to close unused military bases, and Congress has resisted the Air Force's attempts retire aircraft, said Gunzinger, a former deputy assistant secretary of defense. Meanwhile, the Air Force has delayed modernization.