Rupert Murdoch today confirmed he will begin publishing the Sun tabloid seven days a week by publishing a new paper called the Sun on Sunday "very soon".
In a memo to staff, Mr Murdoch also declared his "unwavering support" for the Sun's journalists today and announced he is lifting the suspensions of all arrested staff.
The Sun has been hit by the arrests of 10 current and former senior reporters and executives since November over alleged corrupt payments to public officials.
Mr Murdoch's decision to launch a Sunday version of the Sun was denounced by politicians today as "massively premature".
Labour MP Chris Bryant, who has led the phone-hacking campaign, also described the decision to lift the suspensions on all arrested staff as the “most cynical piece of hypocrisy”.
He said News International had campaigned for public officials who have been charged with criminal offences to be suspended from office but was now apparently not applying the same requirement to its own staff.
Mr Bryant said: “I think it is massively premature because one would have thought the Murdoch empire would want to wait until Leveson had completed his inquiry and the the police and prosecuting authorities had completed their investigations.
“He [Mr Murdoch] is meant still to be ‘draining the swamp’ and yet the swamp is meant to produce another newspaper."
The media mogul, who is visiting the headquarters of his British newspapers in Wapping, east London, sought to reassure Sun staff in a memo.
He wrote: “I have immense respect for our heritage, your exceptional journalism and, above all, you, the talented women and men who work tirelessly every day to ensure our readers have access to such a trusted news source.
“I believe this newsroom is full of great journalists and I remain grateful for your superb work and for the stories you uncover to inform and protect the public.”
He said the recent arrests - including nine in the past three weeks, among them the Sun's deputy editor, picture editor and chief reporter - were "a source of great pain" for him.
Some Sun journalists have expressed anger that News Corporation's Management Standards Committee - formed to clean up the company following the phone-hacking scandal - gave police the information that led to the arrests.
Mr Murdoch said illegal activities “simply cannot and will not be tolerated” but insisted that journalists’ “legitimate” confidential sources would be protected.
He wrote: “I made a commitment last summer that I would do everything I could to get to the bottom of our problems and make this company an example to Fleet Street of ethical journalism.
“We will continue to ensure that all appropriate steps are taken to protect legitimate journalistic privilege and sources, which I know are essential for all of you to do your jobs. But we cannot protect people who have paid public officials.”
The News of the World, the Sun's sister paper, was closed last July after the revelation that it hacked the phone of murdered schoolgirl Milly Dowler following her disappearance in 2002.
PA