How is it possible that secret U.S. military documents could be downloaded and leaked to an organization called WikiLeaks? Apparently, easier than one might think.
American officials condemned the release of more than 90,000 secret files that paint an unflattering light on the U.S.-led war and include references of Afghan civilian deaths and evidence of U.S.-Pakistani distrust.
The Pentagon says it was still investigating the source of the documents. The military has detained Bradley Manning, a former Army intelligence analyst in Baghdad, for allegedly transmitting classified information.
But the latest documents could have come from anyone with a secret-level clearance, Pentagon officials told NBC News.
The Pentagon has various levels of classified Internet sites collectively called "the high-side" or officially SIPRNET, the Secret Internet Protocol Router Network.
Pentagon officials said there are thousands of individuals — Pentagon civilians, military, even private contractors — who share the same level of secret clearance that Manning had that have access to the SIPRNET.
Computers with "the high-side" access are located in computer saferooms at Department of Defense and military facilities worldwide. But, thousands of computers with SIPRNET are setup in individuals' homes or offsite offices and businesses.
One Pentagon official told NBC News that he would log onto the sites in Baghdad and Afghanistan, and said that he could easily download the same kind of secrets that were passed onto WikiLeaks.
Military officials said with that kind of widespread, worldwide access, any "cleared" individual with a personal agenda or grudge could easily become "WikiLeaks next source."
WikiLeaks.org, a self-described whistleblower organization, posted 76,000 of the reports to its website Sunday night. The group said it is vetting another 15,000 documents for future release.
Manning had bragged online that he downloaded 260,000 classified U.S. cables and transmitted them to WikiLeaks.
The White House called the disclosures "alarming" and scrambled to assess the damage.
Col. Dave Lapan, a Defense Department spokesman, said the military would probably need "days, if not weeks" to review all the documents and determine "the potential damage to the lives of our service members and coalition partners."
In latest developments, Adm. Mike Mullen, the chairman of the Joint Chiefs of Staff, told reporters in Baghdad Tuesday that he was "appalled" by the leak.
He said "there is a real potential threat there to put American lives at risk."
Msnbc.com staff and The Associated Press contributed to this report.