NEW YORK — Rocker Jon Bon Jovi donned a New York Police Department T-shirt on stage. Well-wishers delivered home-baked cookies by the hundreds to police in Cincinnati. In Mooresville, N.C., police and sheriff’s officers were treated by residents to a chili dinner.

At a time when many in the nation’s police community feel embattled, Americans in cities and towns across the country are making an effort to express support and gratitude.

“I’m showing a little solidarity for my brothers in the NYPD and all of those who protect and serve us every day,” Bon Jovi told a cheering crowd at his concert Monday in Red Bank, N.J.

The surge of support is linked to two distinct but overlapping developments.

The immediate catalyst was the execution-style killings of two New York City police officers as they sat in their patrol car in Brooklyn on Saturday. For many of those making appreciative gestures, there also was a desire to counter the widespread protests — steeped with criticism of police — that followed grand jury decisions not to charge white officers for their roles in the deaths of black men Michael Brown in Ferguson, Mo., and Eric Garner in New York.