The Pentagon’s top civilian says it’s time to tame burgeoning military personnel costs, but he’s facing a test of wills with the nation’s powerful veterans groups, which want no cut in their benefits.

Veterans groups are fighting curbs in annual pension increases for military retirees under age 62 that are part of the new budget deal passed by Congress last week and awaiting President Barack Obama’s signature. After a barrage of protests from the military community, lawmakers said they’ll review the cut next year and possibly reverse it. But Defense Secretary Chuck Hagel said Thursday that reform of military compensation can’t be avoided.