A huge database of troop names and email addresses a US army private allegedly downloaded to a personal computer could be used by foreign adversaries to launch cyber attacks on service members, a government witness said as the trial of Bradley Manning entered its third week.

A soldier arrested in the biggest leak of classified material in US history, gave the first detailed explanation of his actions today, offering to plead guilty to charges that could send him to prison for 20 years and saying he spilled the secrets to expose the American military’s “bloodlust” in Iraq and Afghanistan.