
The Pentagon said 22-year-old Private First Class Bradley Manning arrived at the Virginia base Thursday night, after being transferred from Camp Arifjan, Kuwait.
Manning already faces four charges related to allegations he gave whistleblowers' website WikiLeaks classified video showing a July 2007 US Apache helicopter strike in Baghdad that killed several people.
He is now also suspected of possible involvement in the bombshell leak to the same website of tens of thousands of classified documents related to the war in Afghanistan.
The Pentagon and the FBI have launched an investigation into the case, while US leaders and Afghan President Hamid Karzai have condemned the leak, citing fears that Afghan informants named in some of the documents could now be at risk.
Top military officer Admiral Mike Mullen on Thursday expressed outrage over the leak, saying the founder of the WikiLeaks website, Julian Assange, may have blood on his hands.
"Mr Assange can say whatever he likes about the greater good he thinks he and his source are doing, but the truth is they might already have on their hands the blood of some young soldier or that of an Afghan family," he said.