Two police officers, a rabbi and a Boy Scout leader are among 70 men and one woman arrested on child pornography charges in a massive operation in New York.

Over five weeks investigators impounded nearly 600 computers, laptops, tablets, smartphones and thumb drives containing tens of thousands of pornographic images and videos of children.

Among the defendants are one with a previous child sex abuse conviction and a woman charged with producing and distributing pornography involving her own young child, US officials said.

They also include two nurses, a paramedic and an au pair.

Officers launched the operation after arresting the head of a police department in Valhalla, New York in January and a rabbi, who home-schooled children in Brooklyn, in March.

James Hayes, special agent in charge of Homeland Security Investigations in New York, described the number of suspects and their professional backgrounds as "troubling".

US officials said Operation Caireen, which ran from 4 April to 15 May, was the largest-ever operation in New York targeting sexual predators of children.

Homeland Security, New York police detectives and other law enforcement infiltrated peer-to-peer file sharing networks to identify perpetrators across the New York City area.

Investigators cracked down on nearly 150 IP addresses actively involved in trading child porn in the wider New York City area.

New York police commissioner William Bratton said the indictment showed "that abuse against children is beyond reproach and violators will be vigorously sought and brought to justice".

"The law enforcement community is committed to eliminating the horrific market for child pornography, one defendant at a time," said US Attorney Loretta Lynch, eastern district of New York.