Cameron also called for "root and branch change" at Murdoch's British newspaper group, News International, and warned that executives found guilty of wrongdoing could be barred from future roles in British media.

His comments heap the pressure on Murdoch as the scandal over voicemail hacking at his News of the World newspaper, which led to the tabloid's closure last week, also threatened to spill over into his US operations.

In a rare show of unity against the one-time kingmaker of British politics, Cameron said his Conservative party would back an opposition Labour motion later Wednesday urging Murdoch to withdraw his bid for control of BSkyB.

"There is a firestorm that is engulfing parts of the media, parts of the police and indeed parts of the political system," Cameron told lawmakers.

Speaking ahead of the debate on BSkyB in parliament, he said: "I think it's good that the House of Commons speak with one voice."

Cameron added that "there needs to be root and branch change at this entire organisation", and said that News International chief executive Rebekah Brooks, a former editor of the News of the World, should no longer be in her job.

He also warned that those found to be responsible for the wrongdoing, which sanctioned it or covered it up, "must also have no future role in the running of a media company in our country".

He said he had personally ensured that a full public inquiry into the scandal, to be led by Lord Justice Brian Leveson, would have the power to summon newspaper proprietors, in a clear nod to Murdoch.

The inquiry will look at press ethics and the relationship between politicians and press.

Murdoch, his son James -- the chairman of BSkyB and an executive at News Corp. -- and Brooks have been called to give evidence to lawmakers next week over phone hacking and claims that newspapers played police for information.

As Cameron spoke, it was reported that Tom Crone, News International's legal manager, had left the company after 26 years.

In the United States, Senate Commerce Committee Chairman Jay Rockefeller called for an investigation to see if the phone-hacking scandal had spread to Murdoch's US operations, saying there could be "severe" consequences.

News Corp's shares have plummeted in the past week, and the Murdoch-owned Wall Street Journal repoted that the media tycoon was considering selling off his remaining British newspapers, The Times, The Sunday Times and The Sun.

The BSkyB bid is seen as key for News Corp. because the satellite broadcaster has a portfolio including live English Premier League football and blockbuster films, and this year reached its target of 10 million household subscribers.

Murdoch's empire wants to buy the 61 percent of BSkyB shares it does not already own.

The Australian arm of News Corp separately announced a review of its editorial expenditure over the last three years.

News Limited chairman John Hartigan said the review would be conducted to reassure the public that illegal phone-hacking practices in Britain had not taken place among his newspapers.

In a heated parliamentary session Wednesday, the British prime minister faced renewed pressure about his former media chief, Andy Coulson, who was editor at the News of the World when two people were jailed for phone hacking in 2007.

Cameron has always said he accepts Coulson's assurances that he knew nothing of the practice but said that it would be a "matter for a criminal prosecution" if Coulson had lied.

British lawmakers on Tuesday grilled senior police officers about how an original probe into the News of the World in 2006, which resulted in the jailing of two people, failed to unearth a trove of further allegations.

News International however went on the offensive against claims by former British Prime Minister Gordon Brown that it had hired "criminals" to access his private information.

The Sun tabloid fought back against claims it used illegal methods to break the news of Brown's son Fraser's cystic fibrosis, splashing the headline "Brown wrong We didn't probe son's medical records" across its front page.

Copyright AFP (Agence France-Presse), 2011