New York  - Some of the largest internet service providers plan to block access to sites connected with child pornography, New York Attorney General Andrew Cuomo announced Tuesday.

The move by Verizon, Sprint and Time Warner Cable marks a significant change in the industry that had previously rejected responsibility for online content.

Verizon and Time Warner Cable are two of the nation's five largest service providers, with roughly 16 million customers between them, and negotiations are continuing with other service providers.

Under the agreement the companies will shutter access to newsgroups that traffic in pornographic images of children on one of the oldest outposts of the internet, known as Usenet. The providers will also cut off access to Web sites that traffic in child pornography.

"The pervasiveness of child pornography on the Internet is horrific and it needs to be stopped," Cuomo said in a statement. "We are attacking this problem by working with internet service providers to ensure they do not play host to this immoral business. I commend the companies that have stepped up today to embrace a new standard of responsibility, which should serve as a model for the entire industry."

Cuomo began pressing for action after undercover investigators found that the companies were not enforcing customer service agreements that threatened users with the risk of losing their service if they trafficked in child porn. The investigation reviewed millions of pictures over several months, uncovering 88 different newsgroups that contained a total of 11,390 sexually lewd photos featuring prepubescent children, and in some cases photos of children being raped and sexual activity involving animals, the attorney general's office said.

Verizon, Time Warner Cable and Sprint provided their subscribers with access to many of these newsgroups.

"You can't help but look at this material and not be disturbed," Cuomo said. "The ISPs' point had been, 'We're not responsible, these are individuals communicating with individuals, we're not responsible.' Our point was that at some point, you do bear responsibility."

The companies will bar access to sites included in a database maintained by the Centre for Missing and Exploited Children.

Investigators also compiled an archive of more than 11,000 child porn images that were searched for using a digital identifier - leading to the discovery of newsgroups and sites dealing in child porn.

The companies as part of the agreements will implement a new system to rapidly respond to user complaints about child pornography. The three companies will also collectively pay 1.1 million dollars to fund additional efforts to remove child pornography from the internet. (dpa)