News Corporation has criticised a key conclusion of a parliamentary committee's report into phone-hacking as "unjustified and highly partisan".
Six members of the Commons media committee said that Rupert Murdoch was "not a fit person" to run a major international business but four others disagreed as it split on party lines.
In response, News Corp admitted it was "too slow" to respond to the crisis.
But it insisted it had "acted on" the failings identified in the MPs report.
In a separate memo to employees of the News Corp-owned Dow Jones, Mr Murdoch admitted mistakes had been made but said his company was "working hard" to put them right and its business had "never been stronger".
The report concluded that Mr Murdoch exhibited "wilful blindness" to what was going on at News Corporation, whose UK newspaper arm has admitted widespread malpractice at the now-closed News of the World (NoW).
The committee also accused three former News International executives - one-time executive chairman Les Hinton, former NoW editor Colin Myler and former legal manager Tom Crone - of giving misleading evidence to Parliament.
But the committee was divided over the decision to include a claim that Mr Murdoch was not "fit" to run a company such as News Corp.
Labour's Tom Watson said Mr Murdoch was more to blame for the hacking scandal "than any individual alive" and the committee was right to censure him - a position backed by four other Labour MPs and one Liberal Democrat on the committee.
But the Conservative MPs on the body said there was no evidence to support this and the judgement was outside their remit.
Tory member Damian Collins told the BBC the reference to Mr Murdoch's suitability to run News Corp was "loaded" and "irresponsible" and risked undermining a "whole raft of charges" against News Corporation which were "powerful stuff" and had the unanimous backing of the committee.
Responding to the report, News Corporation said it had documented "hard truths" about the company's failings over the hacking saga.
"There was serious wrongdoing at the News of the World; our response to the wrongdoing was too slow and too defensive; and some of our employees misled the Select Committee in 2009."
But, in a reference to the claim about Mr Murdoch, it said it regretted that analysis of the "factual record" was followed by "some commentary that we, and indeed several members of the committee, consider unjustified and highly partisan".
BBC business editor Robert Peston said the personal reference to Mr Murdoch was highly significant since it would push Ofcom, the media regulator, closer to the conclusion that BSkyB - 39% owned by News Corp - is not fit and proper to hold a broadcasting licence.
Ofcom said it was "continuing to assess the evidence - including the new and emerging evidence" - that may assist it in ruling on that issue.
The committee of MPs began its inquiry in July 2011 in the wake of fresh revelations about the extent of hacking at the tabloid newspaper, with targets including the mobile phone of murdered schoolgirl Milly Dowler and the families of victims of the 7/7 London bombings.
It concluded that the notion that a hands-on proprietor like Rupert Murdoch had "no inkling" that wrongdoing was widespread at the News of the World was "simply not credible". It said News Corp was guilty of "huge failings of corporate governance" and its instinct had been "to cover up rather than seek out wrongdoing and discipline the perpetrators".
In its statement, News Corp said it had "already confronted and acted on the failings documented" in the report, carrying out reviews of practices at its UK newspapers, making "sweeping changes" to the company's internal controls and giving any evidence of apparent wrongdoing to the police.
Mr Murdoch later responded in person to the report, says its findings had been "difficult to read".
"We certainly should have acted more quickly and aggressively to uncover wrongdoing," he said in a letter of employees of News Corp-owned Dow Jones. "We deeply regret what took place and have taken our share of responsibility for not rectifying the situation sooner."
He added that the company had completed an internal investigation into the practices of journalists at the Sun, the Times and the Sunday Times and this had revealed no fresh evidence of any illegal conduct.
Robert Peston said there was a striking difference between Mr Murdoch's memo, which suggested the Sun was "in the clear", and the News Corp statement which merely said that internal investigations had taken place.
Both Mr Myler and Mr Crone have said they stand by evidence they gave to the committee about what they knew about the extent of hacking and how internal investigations were conducted. Mr Crone said the report contained some "valid criticisms" but insisted claims that he misled Parliament "lacked foundation".
The BBC's Political Editor Nick Robinson said he understood the media committee hoped MPs as a whole would have the chance to vote to censure the three News of the World executives they criticised. But he said it was unlikely the Commons would be asked to pass judgment on the conduct of Rupert Murdoch.