WASHINGTON — President Barack Obama today will announce a two-year pay freeze for federal employees, a move White House officials say is the first of many difficult decisions that must be made to reduce the nation’s mounting deficit.

The White House said today that the freeze would apply to all civilian federal employees, including those working at the Department of Defense, but would not affect military personnel.

The freeze is expected to result in more than $5 billion in savings over two years, according to Jeffrey Zients, a deputy director at the Office of Management and Budget.

That would make only a small dent in the $1 trillion-plus budget deficit. But with voters voicing their anger over Washington’s spending during the midterm elections, even a symbolic gesture could demonstrate the White House got the message.

Zients said that while the freeze is necessary to put the country on sound fiscal footing, the president recognizes the impact it will have on federal employees.

“The president is clearly asking them to make a sacrifice,” he said. “We believe it is the first of many difficult steps ahead.”