Hagel said during a news conference Wednesday the standoff between the White House and Congress over a comprehensive tax-and-spend deal has forced the Pentagon to plan for a range of cuts, since a deal to lift the sequester hasn't happened, The New York Times reported.
Under the deepest-cuts scenario, Hagel said he had several choices: The military could maintain its size but not buy the most advanced new weapons or the Pentagon could reduce the force and invest in next-generation of weaponry.
Hagel said a reduction in force would reduce the active-duty U.S. Army to 380,000-450,000 troops and a reduction in the U.S. Marines to 150,000-175,000 personnel. Under the current budget, Army personnel will fall over five years to 490,000 and the Marines are to drop to 182,000 from 202,000.
Cuts also could include a concurrent reduction in U.S. Navy aircraft carrier strike groups from 11 to eight or nine, as well as the retirement of some U.S. Air Force squadrons.
"This strategic choice would result in a force that would be technologically dominant but would be much smaller and able to go fewer places and do fewer things, especially if crises occurred at the same time in different regions of the world," Hagel said.
The other option -- maintaining a sizable military -- would mean canceling or curtaining weapons programs, slowing development of cyberwarfare tools and reducing the number of Special Operations forces, Hagel said.