The commissioner of the country's largest police force is stepping down.

FOX's Gurnal Scott's reports from New York City:

New York City Mayor Bill de Blasio spoke in glowing terms about the contributions to the N.Y.P.D. under two mayors by Commissioner Bratton:

(Bratton) "Whose contributions to our city and to law enforcement not only here, but across the nation are literally inestimable." 

The Commissioner got emotional as he reflected on the people he credits for shaping his life and values:

(Bratton) "Two of the best parents that anyone could ever have hoped to have had, Bill and June Bratton and I really wish they could have been here to see this day." 

Bratton's top chief James O'Neill will replace him in September.

Gurnal Scott, FOX News.

Follow Gurnal Scott on Twitter: @GurnalScott