Burson-Marsteller has admitted its firm was hired by Facebook to launch a campaign that called into question Google's privacy tactics.

An earlier report from The Daily Beast, said the popular social networking company hired the PR firm Burson-Marsteller to plant and pitch anti-Google stories to the media. The stories were about Google invading people's privacies and their lax stance on privacy in general. Burson-Marsteller pitched the story to a popular privacy blogger, who then turned it around on them and published the email exchange with the original pitch.

Now that Facebook has come forward, we can confirm that we undertook an assignment for that client, said the spokesperson for Burson-Marsteller.

According to Burson-Marsteller, Facebook was simply trying to point out information, that is already available for public viewing, and raise some fair questions.

The client requested that its name be withheld on the grounds that it was merely asking to bring publicly available information to light and such information could then be independently and easily replicated by any media.  Any information brought to media attention raised fair questions, was in the public domain, and was in any event for the media to verify through independent sources, the spokesperson said.

However, the report from The Daily Beast, says Facebook's motives for this PR campaign go beyond this simple explanation. While Facebook does believe Google is doing things in social networking that raise privacy concerns, Facebook is miffed at Google for using its data for its Social Circle service.

Meanwhile, the spokesperson for Burson-Marsteller, said the PR agency should have declined the assignment since it is against its standard operating procedures and policies.

When talking to the media, we need to adhere to strict standards of transparency about clients, and this incident underscores the absolute importance of that principle, the spokesperson said.

Until this incident, the Facebook-Google rivalry was lukewarm compared to other tech enemies (HP-Oracle, HP-Dell and Intel-Anyone In Semiconductors). The only notable interchange between the two companies was when Facebook hired a bunch of old Google executives, engineers and technicians. There were also rumors Google was building a social network to counter Facebook, but the only thing that ever amounted was its Buzz service.

Facebook and Google did not respond to an inquiry for comment.

Follow Gabriel Perna on Twitter at @GabrielSPerna