Earlier this week Adm. Mullen said that WikiLeaks and its founder, Julian Assange, might have "blood on the hands," from a soldier or Afghan whose identity might be compromised by the leak.
On CBS' "Face the Nation" today, Mullen said he was concerned about the potential for damage.
"I very much meant what I said," he told host Harry Smith, and said his fears were "specifically endorsed by the Taliban leadership which has come out in the last day or so and said that they in fact are looking at the names that are leaked. I certainly think that's an indicator of what's possible."
Mullen said people outside the military may not understand the danger of such leaks. "The ability to knit together what is seemingly information that may not be related and then to take advantage of it, I think it's, you know, it's irresponsible and could very well potentially end up in the loss of lives," he said.
Mullen did not say whether there was evidence that the release of the information has lead to harm against U.S. forces or collaborators, but said that the U.S. is seeking to protect informants named in the leaks.
"There are certainly efforts going on to do that. But I couldn't speak to specifics right now," he said. "I think Secretary Gates said it earlier in the week, we do have a moral obligation given their exposure and given what they've done, to do all we can to ensure their safety."
When asked if he thought there was anything the government could do to prevent the release of additional documents, Mullen replied, "Well, there's obviously an investigation which is open and expanding as necessary.
"I actually feel very strongly that the release of additional information could continue to jeopardize [people], as I've indicated. I'm not specifically aware of any action that's been taken in the government to bar anybody from leaking more information."