Authorities arrested eight people Saturday -- including five journalists of Britain's bestselling Sun newspaper -- as part of an inquiry into alleged illegal payments to police and officials.

The other three are a police officer, an employee of the Ministry of Defence and a member of the armed forces, the Metropolitan Police said.

A search was carried out at News International's offices in east London, the police said, as well as the homes of those arrested. News International, which owns the Sun, is a U.K. subsidiary of media mogul Rupert Murdoch's News Corp.

Following the arrests, Murdoch, chairman and CEO of News Corp, issued a personal assurance to one of his executives to continue to own and publish The Sun newspaper, according to an internal staff memo sent by News International Chief Executive Tom Mockridge.

Mockridge also said he was "very saddened" by the arrests of deputy editor Geoff Webster, picture editor John Edwards, chief reporter John Kay, chief foreign correspondent Nick Parker, and John Sturgis, who is a news editor. The five journalists were arrested at their homes, police said.

"I understand the pressure many of you are under and have the greatest admiration for everyone's continued professionalism," Mockridge wrote.

"The Sun has a proud history of delivering ground-breaking journalism. You should know that I have had a personal assurance today from Rupert Murdoch about his total commitment to continue to own and publish The Sun newspaper.

"Today we are facing our greatest challenge," Mockridge said.

The Sun's editor, Dominic Mohan, said in a statement: "I'm as shocked as anyone by today's arrests but am determined to lead The Sun through these difficult times.

"I have a brilliant staff and we have a duty to serve our readers and will continue to do that. Our focus is on putting out Monday's newspaper."

Mohan has said the paper has a readership of more than 7.7 million.

The arrests are part of Operation Elveden, an investigation running in parallel with a police inquiry into alleged phone hacking by the media, the police statement said. Late Saturday, all eight people were released after posting bail, police said.

News Corp.'s Management and Standards Committee said it had provided the information to the Elveden investigation which led to Saturday's operation. Elveden has been widened out to include alleged corruption involving public officials, as well as the police.

The five journalists, with ages between 45 and 68, were arrested at their residences in London, Kent and Essex on suspicion of corruption, aiding and abetting misconduct in a public office, and conspiracy in relation to both offenses, police said.

News Corp. said in a statement that it "remains committed to ensuring that unacceptable news gathering practices by individuals in the past will not be repeated."

The other three suspects were arrested on suspicion of corruption, misconduct in a public office, and conspiracy in relation to both these offenses.

A 39-year-old officer with Surrey Police is being questioned at a London police station, the Met Police said.

The Ministry of Defence employee, a 39-year-old woman, is being questioned at a police station in Wiltshire, as is the member of the armed forces, a 36-year-old man.

The police said the operation "relates to suspected payments to police officers and public officials and is not about seeking journalists to reveal confidential sources in relation to information that has been obtained legitimately."

The Ministry of Defence said it was a matter for the Metropolitan Police and that it could not comment on an ongoing police investigation.