UK police want paper to reveal phone-hacking sources

British police are seeking an "unprecedented" court order to force the newspaper that led the coverage of a phone-hacking scandal engulfing Rupert Murdoch's News Corp empire to reveal its sources, the paper said on Friday.

In a story on its website, the left-leaning Guardian said London's Metropolitan Police (MPS) was trying to use the Official Secrets Act to force two of its reporters to disclose their confidential sources.

The act is designed to protect classified information and is usually applied to matters of national security and espionage.

The Guardian newspaper's reports have helped keep the story at the top of the political agenda in Britain and played a part in forcing News Corp to close the 168-year-old News of the World tabloid at the centre of the scandal.

The story has pulled in Murdoch's son James, forced News Corp to withdraw a bid to buy the part of pay TV group BSkyB it did not already own and shaken the British political establishment.

Britain's most senior police officer and the top counter-terrorism officer also quit amid a growing furore.

The Guardian said the police wanted to use the act to find the source of information that led to the revelation in July that murdered schoolgirl Milly Dowler's phone had been hacked.

The disclosure caused a wave of public anger which ultimately brought about the downfall of the News of the World, and led to the resignation of Rebekah Brooks, chief executive of News International, the British newspaper arm of News Corp.

"We shall resist this extraordinary demand to the utmost," the Guardian's editor Alan Rusbridger said in the online report.

Detectives are investigating the phone-hacking allegations and have already arrested 16 people including Brooks and Andy Coulson, the former editor of the News of the World who went on to work as Prime Minister David Cameron's media chief.

One of the detectives involved in the investigation was also arrested and suspended last month on suspicion of leaking details about the case.

The paper was the first to report a number of the high-profile arrests in the phone-hacking inquiry. One of the Guardian's reporters was quizzed by police investigating the leaks.