New York City police have plans to put body cameras on all 23,000 of its patrol officers by 2019, an ambitious effort that would dwarf all others across the country.

But the nation's largest police department is lagging behind other cities, with only limited experience with the cameras. The force currently has none in use on the streets.

Mayor Bill de Blasio says his body camera plan proposed last month is crucial to restoring trust between officers and the communities they serve.

A federal judge ordered the NYPD to try out body cameras as part of a 2013 ruling that found the department was wrongly targeting minorities with its stop-and-frisk tactic.