A US judge has ruled that "stop-and-frisk" searches, carried out by the New York City Police, are unconstitutional.

Civil rights groups have long argued that the controversial tactic amounts to racial profiling.

But New York City mayor Michael Bloomberg says it is one of his most successful measures for cutting down on crime.

A federal monitor will now be appointed to oversee the department as it works to correct the problem.

Al Jazeera's Kristen Saloomey reports from New York City.