Two journalists were arrested today by detectives investigating corrupt payments to public officials.
Justin Penrose, crime correspondent of the Sunday Mirror, and Tom Savage, deputy news editor of the Daily Star Sunday, were the latest to be held.
They are being questioned at separate police stations on suspicion of conspiracy to corrupt and of conspiracy to cause misconduct in a public office.
Scotland Yard said: "Today's arrests relate to suspected payments to a public official and are not about seeking journalists to reveal confidential sources in relation to information that has been obtained legitimately."
The latest arrests mean 41 people have been arrested by detectives on Operation Elveden, the investigation into suspected corrupt payments to public officials.
It is being run alongside Operation Weeting, the Scotland Yard probe into phone hacking.
A Yard spokesman said: "A 37-year-old man was arrested at his home in Kent and a 34-year-old man at his home in south-east London at approximately 6am on suspicion of conspiracy to corrupt (contrary to the Prevention of Corruption Act 1906) and of conspiracy to cause misconduct in a public office (contrary to common law).
"The two, both journalists, are being questioned at police stations in Kent and south-east London."
Trinity Mirror said Sunday Mirror reporter Justin Penrose had been arrested.
A spokesman said: "We have been informed by the police that Justin Penrose was arrested this morning on suspicion of alleged payments to public officials. We are co-operating fully with the police."
Mr Penrose has worked for the Sunday Mirror since 2004, and was made crime correspondent in 2006.
In evidence to the Leveson Inquiry into press ethics, Mr Penrose said the newspaper never paid police for stories.
In a written statement, addressing the question of what ethical issues need to be held in mind by a journalist communicating with the police, he said: "The main ethical issue is that we never pay police officers for stories or seek to put the police in a position where they feel that they should provide information to us in exchange for anything that they consider that they are getting from us."
He also warned that there was a "climate of fear" stopping officers talking to the Press.
He wrote: "I believe that officers should be allowed to speak to the Press about their cases without the fear that they are going to be accused of corruption. At the moment there is a climate of fear in which officers are too scared to talk to the Press."
A spokesman for Express Newspapers, publisher of the Daily Star Sunday, said: "We can confirm that one of our reporters was arrested this morning as part of Operation Elveden and we are working closely with the authorities in relation to this matter."
Trinity Mirror said officers searched Mr Penrose's desk this morning and took away "various items", including his computer.
A spokesman said: "Following a prearranged meeting at 11am, the police now have in their possession various items from Justin Penrose's desk, including his computer.
"There is no further comment to make at this stage."