Government snooping into phone networks is extensive worldwide, one of the world's largest cellphone companies revealed Friday, saying that several countries demand direct access to its networks without warrant or prior notice.

The detailed report from Vodafone, which covers the 29 countries in which it operates in Europe, Africa and Asia, provides the most comprehensive look to date at how governments monitor mobile phone communications. It amounts to a call for a debate on the issue as businesses increasingly worry about being seen as worthy of trust.

Wiretapping of phones and accessing of call records for law-enforcement purposes is a decades-old and accepted practice even in the most open democracies. With backing from courts, police can request cooperation from phone companies, a valuable tool for the pursuit of criminals.

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But the most explosive revelation in Vodafone's report is that in six countries, authorities require direct access to an operator's network — bypassing legal niceties like warrants and eliminating the need to get case-by-case cooperation from phone-company employees. It did not name the countries for legal reasons and to safeguard employees working there.

"In those countries, Vodafone will not receive any form of demand for lawful interception access as the relevant agencies and authorities already have permanent access to customer communications via their own direct link," the report said.

Vodafone's report comes one year after documents leaked by former NSA systems analyst Edward Snowden revealed that the U.S. and other countries' intelligence agencies routinely and indiscriminately gather and store huge amounts of data from phone calls and Internet communications.

The revelations have focused particular attention on the role of Western technology and telecommunications firms, which stand accused of facilitating the mass surveillance by giving spies unrestricted access to their networks. Several Silicon Valley companies have since attempted to restore consumers' trust by publishing data on government surveillance.

People walk past a Vodafone shop in London on Friday. Lefteris Pitarakis / AP

But telecoms companies found themselves in an even more uncomfortable position. Historically closer to governments since many were once state-owned, telecoms companies are much more heavily regulated and have employees on the ground — making them more sensitive to government demands for data.

By making its report public, together with a breakdown on requests for information, Vodafone took the unusual step of entering the international debate about balancing the rights of privacy against security. Rather than being stuck with responsibility and consumer backlash when consumers realize their data has been scooped up without their knowledge, companies like Vodafone have decided it is time to push for a debate.

"Companies are recognizing they have a responsibility to disclose government access," Daniel Castro, senior analyst for the Information Technology and Innovation Foundation in Washington, D.C. "This is new."

The study comes at a time when other businesses are also calling for a revamp of laws too outdated to stand up to the quickly changing telecommunications universe.

Executives in Silicon Valley, for example, have stepped up pressure on President Barack Obama to curb the U.S. government surveillance programs that collect information off the Internet.

— The Associated Press