Two Special Forces officers have reportedly been arrested over alleged breaches of the Official Secrets Act.
Four searches were carried out but details of the information suspected of being leaked has not been released.
The Ministry of Defence confirmed that two members of the armed forces were arrested last month.
Scotland Yard said two men were held on 2 March and taken to police stations in London before being released on bail until dates in May.
A Metropolitan police spokesman said: "Officers arrested two men aged 33 and 35, on suspicion of breaching the Official Secrets Act 1989. Both men were taken to a central London police station.
"On Thursday, March 3 both men were bailed to return to a police station."