London (CNN) -- An officer working on an inquiry into alleged phone hacking by the News of the World newspaper has been arrested on suspicion of leaking information, police in London said Friday.
The detective, a 51-year-old man, was arrested at work Thursday "on suspicion of misconduct in a public office relating to unauthorised disclosure of information," the Metropolitan Police said. He was suspended Friday.
More than a dozen people have been arrested in connection with the investigation into claims of phone hacking by the News of the World, known as Operation Weeting.
Deputy Assistant Commissioner Sue Akers, in charge of the operation, said: "I made it very clear when I took on this investigation the need for operational and information security. It is hugely disappointing that this may not have been adhered to."
She said the police took the "unauthorized disclosure of information extremely seriously" and had acted swiftly to make arrests.
A 35-year-old man was also arrested and released on bail in London Friday on suspicion of conspiring to unlawfully intercept voice mails, the police said.
A second police investigation, known as Operation Elveden, is examining claims that bribes were paid to police.
Earlier, a representative of the High Court in London told CNN that News of the World's private investigator Glenn Mulcaire is being forced to reveal who ordered him to hack celebrities' phones.
The order was made by a judge July 19 but has only just been made public, the court representative said.
News of the World, the country's best-selling Sunday tabloid, was shuttered last month amid a scandal over allegations that its staff members hacked the phones of people ranging from celebrities to crime victims.
News International, which ran the News of the World newspaper, confirmed Thursday that Mulcaire was taking legal action against the company. The claim would be "vigorously contested," the company said.
Mulcaire was jailed for intercepting royal voice mail in 2007, along with News of the World's royal correspondent Clive Goodman.
When police arrested Mulcaire in 2006, they seized 11,000 pages of documents with the names of 3,870 potential victims of illegal eavesdropping.
Mulcaire released a statement through his lawyers last month in which he suggested that he did not bear sole responsibility for any wrongdoing.
"As an employee, he acted on the instructions of others. There were also occasions when he understood his instructions were from those who genuinely wished to assist in solving crimes," the statement said.
"Any suggestion that he acted in such matters unilaterally is untrue."
Senior executives at News International, which is the British arm of Rupert Murdoch's News Corp. media empire, have said that any wrongdoing at News of the World was not widespread.
CNN's Dan Rivers and Jonathan Wald contributed to this report.