WASHINGTON  Defense Secretary Robert M. Gates said Monday that he would close a military command, restrict the use of outside contractors and reduce the number of generals and admirals across the armed forces as part of a broad effort to rein in Pentagon spending.

Mr. Gates did not place a dollar figure on the total savings from the cutbacks, some of which are likely to be challenged by members of Congress intent on retaining jobs in their states and districts. But they appear to be Mr. Gates’s most concrete proposals to cut current spending as he tries to fend off calls from many Democrats for even deeper budget reductions, and they reflect his strategy of first trying to squeeze money out of the vast Pentagon bureaucracy.

While large headquarters have been combined and realigned over the years, Pentagon officials could not recall a time when a major command was shut down and vanished off the books, even though some jobs will probably be added elsewhere to carry on essential parts of the mission.

The White House, which is under intense political pressure to address the rapid increase in the national debt, quickly stepped in to back Mr. Gates, saying his plan would free money that could be better spent on war fighting.