Detectives investigating alleged phone-hacking at the 'News of the World' arrested the paper's chief reporter and former head of news yesterday.
Neville Thurlbeck (50) and Ian Edmondson (42) were held by Scotland Yard detectives when they voluntarily attended separate police stations in south-west London.
A police spokesman said last night that two men who had been arrested in connection with the investigation had been released on bail.
Officers questioned the pair on suspicion of conspiring to intercept communications and unlawfully intercepting voicemail messages.
The arrests underlined the police's determination to investigate the scandal thoroughly after criticism that an earlier inquiry was inadequate.
Mr Thurlbeck is a veteran reporter who has brought in some of the 'News of the World's most famous scoops, while Mr Edmondson was sacked as assistant news editor in January after evidence emerged linking him to phone-tapping.
They were the first people arrested since Scotland Yard reopened its inquiry into claims that staff at the newspaper hacked into the answerphone messages of celebrities, politicians and royals.