Speaking on ABC's 'This Week', Gates said, "My attitude on this is that there are two areas of culpability. One is legal culpability. And that's up to the Justice Department and others. That's not my arena. But there's also a moral culpability. And that's where I think the verdict is guilty on WikiLeaks."
"They have put this out without any regard whatsoever for the consequences," he added, slamming the website for showing "no sense of responsibility."
In an interview with NBC, Chairman of the Joint Chiefs of Staff, Admiral Mike Mullen, also expressed concern about the potential damage that the leak of the secret documents could do.
"The potential for costing us lives I think is significant," Mullen said, stressing that the publication of the information could endanger people, operations and "outcomes."
In a separate interview on CBS' 'Face the Nation', the top US military official said the US government is trying to protect its Afghan informants in the wake of the leak.
This statement gains significance after the Taliban issued a death threat to all the US informants.
The authorities had already predicted a development like this and had said that the WikiLeaks founder, Julian Assange, has 'blood on his hands' after the trove of war documents were posted online.