Police investigating phone hacking at the News of the World were set Saturday to extend their probe into claims that computers were hacked, in a fresh threat to Rupert Murdoch's embattled empire.

The Metropolitan police said late Friday it was establishing a new team of officers to examine claims which emerged during its current phone-hacking investigation that computers may have also been illegally accessed.

The move heaped further pressure on Murdoch's embattled News Corp. conglomerate the same day an investigator at the heart of the controversy said he acted on orders from News of the World (NotW), axed this month as the scandal erupted.

Private detective Glenn Mulcaire's comments are a challenge to claims by Murdoch's empire that he was a rogue operator.

Meanwhile a parliamentary committee said it had ordered Murdoch's son and heir apparent James to give written clarification of answers he gave on the scandal last week.

Murdoch has been struggling for weeks to stem the spiralling scandal, which has dragged in police and politicians and spread to the United States and Australia.

But there was little sign Saturday that the crisis was about to die down, with police laying the ground to start probing allegations of computer hacking.

An inquiry, Operation Tuleta, was "currently considering a number of allegations regarding breach of privacy... including computer hacking" that were not covered by the current phone-hacking probe, Scotland Yard said in a statement.

A team was being established to look into the claims and "some aspects of this operation will move forward to a formal investigation," said the statement.

The police have faced fierce criticism over their failure to properly investigate hacking allegations during an initial probe in 2006.

That investigation led to the jailing of the NotW's royal editor and Mulcaire in 2007 but despite mounting evidence that hacking was more widespread than the paper originally claimed, the police only revived the probe this year.

Two top officers have been forced to resign over the scandal along with several top Murdoch aides.

Elsewhere, Mulcaire's intervention focused attention back on the issue of how much key figures at News Corp. knew about hacking.

In a statement issued by his lawyers, Mulcaire expressed "sincere regret" but he added that he was "effectively employed" by the paper from 2002.

"Any suggestion that he acted in such matters unilaterally is untrue," the statement said.

He spoke a day after the mother of a murdered eight-year-old girl said police had confirmed her details were found among his papers. Claims that he hacked the phone of a murdered 13-year-old ignited the scandal earlier this month.

Rebekah Brooks, editor of the News of the World from 2000-2003, and her successor until 2007, Andy Coulson, have both denied authorising any phone hacking or knowing that the practice was being used by their staff.

Brooks and Coulson, who went on to become Prime Minister David Cameron's media chief until January this year, have since been arrested.

James and Rupert Murdoch, along with Brooks, who quit as chief executive of News Corp.'s British newspaper wing News International earlier this month, answered questions from parliament's media committee on July 19.

Committee chairman John Whittingdale said Friday that he would be writing to James Murdoch about his testimony to the committee and that "the chances are" he would be recalled to clarify his evidence.

Ex-NotW editor Colin Myler and legal manager Tom Crone last week said James Murdoch gave misleading evidence about how much he knew about the extent of hacking at the paper when he authorised a payout to a victim in 2008.

It was at that hearing that the 80-year-old Rupert Murdoch was hit in the face with a plateful of shaving foam by comedian Jonathan May-Bowles.

May-Bowles, 26, whose stage name is Jonnie Marbles, pleaded guilty Friday at City of Westminster Magistrates Court to assault and to causing harassment, alarm or distress. A judge told him he faces jail when sentenced on Tuesday.

James Murdoch has also faced calls to quit his chairmanship of pay-TV giant BSkyB. But his position was strengthened Friday when the company posted bumper operating profits of £1.073 billion in the 12 months to June, up 23 percent on the previous year.

The Times meanwhile reported Saturday that Prince William expressed disappointment to James Murdoch and Brooks that no one from News International had apologised to him after his aides' phones were hacked several years ago.

During a lunch meeting in January at a north Wales hotel, Murdoch and Brooks reportedly offered their apologies to him.