Mayor Rahm Emanuel is sending layoff notices to about 625 city of Chicago employees — and delaying 61 blocks of curb and gutter improvements and 76 blocks of sidewalk repairs — after union leaders didn’t agree to work-rule changes the mayor wants or offer alternate ways to cut costs by a deadline Friday.

“My duty as mayor is to protect our city’s taxpayers and be their voice — not to protect the city’s payroll,” Emanuel said at a City Hall news conference Friday. “No amount of smoke and mirrors can put off the tough decisions any longer.”