News Corp. chief executive Rupert Murdoch on Friday warned staff at his scandal-hit British tabloid The Sun that he won't protect reporters found to have broken the law, but pledged unstinting support to the title he claimed is among his proudest achievements.

The media mogul, who flew on Thursday to Britain from the United States to tour The Sun's London newsroom amid a simmering staff revolt, pledged to restore the newspaper's status and confirmed plans to soon launch a new Sunday edition to replace the shuttered News of the World.

In an emailed message to staff, Murdoch confirmed he will remain in London "for the next several weeks to give you my unwavering support" amid the crisis caused by Britain's phone hacking scandal and police investigations into alleged email hacking and purported bribery of public officials.

Murdoch's visit follows last week's arrest of five senior staff at The Sun in raids at their homes in an inquiry into the alleged payment of bribes to police and defence officials for information. A total of 10 current and former staff at The Sun — Britain's biggest selling newspaper — have been questioned over the allegations. None has so far been charged.

Accompanied by son Lachlan

"We will obey the law. Illegal activities simply cannot and will not be tolerated — at any of our publications," Murdoch said in his email, which was forwarded to The Associated Press. He added that his media empire "cannot protect people who have paid public officials."

Murdoch chatted to reporters in The Sun's newsroom but did not make a formal speech to staff and was accompanied on his tour by his eldest son Lachlan, not his younger son James — who is chairman of News International. Officials at the company insisted James was out of Britain and had other commitments.

A small group of protesters gathered outside News International's London offices — also home to Murdoch's broadsheet titles The Times and The Sunday Times — raising placards that read "End the Murdoch Mafia."

Britain's media, police and political class have been engulfed in scandal since last summer, when it was disclosed that journalists at Murdoch's News of the World tabloid had routinely eavesdropped on the private cell phone voicemail messages of celebrities, sports figures, politicians and crime victims.

Since Murdoch closed the 168-year-old tabloid in July, police have made almost 40 arrests — detaining several reporters — over phone hacking and in two related inquiries into the alleged use of bribes and email hacking. Millions of dollars have been paid out by Murdoch's company so far in out-of-court settlements to about 60 victims of hacking.

Cherished tabloid

Two top London police officers and several senior Murdoch executives have resigned in the scandal, which also prompted Andy Coulson — a former News of The World editor — to quit as Prime Minister David Cameron's communications director. Cameron ordered a judge to lead a national inquiry into media ethics, which has seen celebrities and news executives give testimony in weeks of televised hearings.

Murdoch, 80, confirmed that staff currently suspended amid the police inquiries involving his newspapers would be allowed to return to their posts and have their legal fees paid. He pledged to help The Sun, which he has owned since 1969, recover from the crisis and said his cherished tabloid was "part of me and is one of our proudest achievements."

"We will build on The Sun's proud heritage by launching The Sun on Sunday very soon," Murdoch's email read, confirming a long anticipated announcement that the tabloid would become a seven-day-a-week title. "Our duty is to expand one of the world's most widely read newspapers and reach even more people than ever before."

News International, the British arm of News Corp., said it could not confirm precisely when the new title would launch.

Murdoch's visit, which officials insisted had long been planned, came amid a mutinous mood at The Sun. Some staff at News International have expressed alarm after both the company and police confirmed the latest arrests of reporters came after executives supplied information to detectives.

Several million old emails

Others have raised worries that details of their confidential sources may have been passed to police.

After insisting that wrongdoing had been confined to a single reporter jailed in 2007, News Corp. appointed a management and standards committee last summer to investigate the extent of malpractice at its British newspaper subsidiary. The committee, which reports to News Corp. executive vice president Joel Klein, is scrutinizing several million old emails and other documents.

Murdoch said the committee had been instructed to co-operate with the police. "We will turn over every piece of evidence we find — not just because we are obligated to but because it is the right thing to do," he said in his email.

National Union of Journalists General-Secretary Michelle Stanistreet said Murdoch was sending out "mixed messages" to staff and was using the announcement of his new Sunday tabloid in an attempt to quell dissent. Reporters have complained that rank and file staff have not received the same support as senior managers.

Trevor Kavanagh, The Sun's associate editor, told the BBC on Monday that many staff were uneasy about the activities of the management standards committee. He said some executives were "actually boasting that they're sending information to the police."