The Electronic Freedom Foundation (EFF) is suing the US Department of Defense (DoD) for failing to come clean on a campaign to monitor soldiers' blogs.

The EFF formally requested details of the programme under the Freedom of Information Act, but went to court after the DoD failed to provide any details.

The complaint alleges that the DoD undertook systematic blog monitoring, and sought to delete information that it did not like. 

"If the Army is colouring or curtailing soldiers' published opinions, Americans need to know about that interference," said EFF staff attorney Marcia Hofmann.

"Of course, a military effort requires some level of secrecy. But the public has a right to know if the Army is silencing soldiers' opinions as well. That is why the DoD must release information on how this programme works without delay. "

According to news reports, the DoD set up a special group to monitor the blogs and electronic mail of troops under an initiative called the Army Web Risk Assessment Cell.

Some bloggers have told reporters that they have cut back on their posts, or shut down their sites altogether, because of the monitoring programme.