
In a statement, Facebook COO Sheryl Sandberg also denied any information about the firm.
The attack on Zuckerberg is set to complicate the daunting challenge facing Sir Nick Clegg, Facebook's new global head of policy and communications, who joined last month and has been asked to conduct a review of Facebook's use of lobbying firms. "That, they have assured me, was not happening", Sandberg told CBS This Morning.
"These were known traditional cyberattacks like hacking and malware", Sandberg said.
She said she was unaware Facebook was working with Definers.
San Francisco: Facebook investors have mounted pressure on Chairman and CEO Mark Zuckerberg to step down from chairman post following a New York Times report which said that the social network hired a Republican-owned political consulting and PR firm that "dug up dirt on its competitors".
The Hungarian-born United States financier and philanthropist is a favorite target of nationalists and anti-Semitic conspiracy theorists. And again, we're doing a thorough look into what happened but they have assured me that we were not paying anyone to either write or promote anything that was false. "After reading the article, I got on the phone with our team and we are no longer working with this firm", he said.
"I have great respect for George Soros - and the anti-Semitic conspiracy theories against him are abhorrent".
"These efforts appear to have been part of a deliberate strategy to distract from the very real accountability problems your company continues to grapple with", wrote Patrick Gaspard, the president of the Open Society Foundations, a philanthropic organisation founded by Soros.
"And frankly now that we know that they ran this black ops operation, there are questions about why they're following the model of people like Vladimir Putin".
USA senators called on Facebook founder and chief executive Mark Zuckerberg to also respond to the New York Times' allegations yesterday, which included attempts by Facebook to downplay Russian interference in the 2016 Presidential election, and to discredit activist investors such as billionaire George Soros.
It also said that the company also used a Republican public relations firm, Definers Public Affairs, to help fix its battered reputation following intense criticism of the social media platform's handling of a scandal over Russian interference in the 2016 U.S. elections and the Cambridge Analytica scandal, The Telegraph reported.
"This practice, standard across many industries, is based on researching public records and databases available to anyone".