Detectives on Saturday searched the offices of Rupert Murdoch's The Sun and arrested four journalists and a policeman in a widening probe into the bribing of police for information.
The development finally drags Britain's biggest-selling newspaper into the turmoil at Murdoch's empire, after its stablemate the News of the World was shut down in disgrace in July amid a scandal overphone hacking.
Police said they made the arrests after information was provided to police by Murdoch's US-based News Corporation -- in what commentators said was a clear effort by the company to detoxify the brand.
The BBC and the Guardian newspaper named the arrested Sun journalists as former deputy editor Fergus Shanahan, former managing editor Graham Dudman, current crime editor Mike Sullivan and current head of news Chris Pharo.
In an email to staff, Tom Mockridge, the chief executive of Murdoch's British subsidiary News International, said Saturday that the company had provided legal support to the arrested men.
"Despite this very difficult news, we are determined that News International will emerge a stronger and more trusted organisation," Mockridge wrote in the email, a copy of which was obtained by The Guardian.
"We must all support Dominic (Mohan, the editor of The Sun) who will be leading his staff to deliver, as always, a great paper for Monday and going forward."
Scotland Yard said in a statement that in dawn raids it had arrested two men aged 49 and 57 at their homes in Essex, and a man aged 48 at his home in London.
A 42-year-old man was later arrested after attending a police station.
They were held on suspicion of corruption, aiding and abetting misconduct in a public office and conspiracy in relation to both these offences.
A 29-year-old from the force's Territorial Policing command was arrested at the London police station where he works on suspicion of corruption, misconduct in a public office and conspiracy.
"The home addresses of those arrested are currently being searched and officers are also carrying out a number of searches at the offices of News International in Wapping, East London," a police statement said.
"Today's operation is the result of information provided to police by News Corporation's Management and Standards Committee.
"It relates to suspected payments to police officers and is not about seeking journalists to reveal confidential sources in relation to information that has been obtained legitimately."
News Corp. confirmed that the other four men arrested either worked or used to work at The Sun.
It said it had set up the committee after the phone-hacking scandal "to undertake a review of all News International titles, regardless of cost, and to proactively cooperate with law enforcement and other authorities if potentially relevant information arose at those titles."
"As a result of that review, which is ongoing, the (committee) provided information to the Elveden investigation which led to today's arrests."
Thirteen people have now been arrested under Operation Elveden, the police investigation into allegations that journalists paid officers for information.
It was sparked by concerns about the working practices of the British press after the News of the World scandal and runs alongside Operation Weeting, the probe into phone hacking under which 17 arrests have so far been made.
The scandal at the News of the World erupted in July when it emerged that journalists had listened to the voicemails not just of celebrities and politicians but also a murdered schoolgirl, Milly Dowler.
Amid public outrage, Murdoch closed down 168-year-old weekly.
The scandal also prompted Prime Minister David Cameron to order a wide-ranging inquiry into the practices and ethics of the press, which began hearings at the end of last year.
The Sun has daily sales of more than 2.5 million. It is known for its racy celebrity-driven content and colourful headlines, but also for self-proclaimed influence with the electorate.
Ahead of elections in 2010 it dropped its support for British prime minister Gordon Brown's Labour party in favour of Cameron's Conservatives.
Current Sun editor Mohan told the phone-hacking inquiry earlier this month that he had no knowledge of phone-hacking at the paper, adding that the daily could be a "powerful force for good."