"I remain true to the ideals I have expressed. This circumstance shall not shake them," Assange wrote, according to a Australia's 7 News Tuesday. "If anything this process has increased my determination that they are true and correct."
Last week, U.S. Attorney General Eric Holder said the release of the documents had put the United States at risk and said he authorized a criminal investigation into Assange.
"The lives of people who work for the American people has been put at risk; the American people themselves have been put at risk by these actions that are, I believe, arrogant, misguided and ultimately not helpful in any way. We are doing everything that we can," Holder said Tuesday. "We have a very serious, active, ongoing investigation that is criminal in nature. I authorized just last week a number of things to be done so that we can hopefully get to the bottom of this and hold people accountable, as they -- as they should be."
Outspoken critics of the document drop, including President Obama and Secretary of State Hillary Clinton, said they believe the formerly classified material is more than just embarrassing for the slights against foreign leaders, but potentially disastrous for U.S. strategy abroad.
"We have gotten indications that there is at least some change in how individuals and governments cooperate with us, and share information," Pentagon spokesman Col. Dave Lapan said last week. There's a vague "sense that there has been some pulling back because of these revelations."
Speaking a press conference Monday, Secretary of State Hillary Clinton said the leak could "create potential dangers for our friends and partners."
ABC News' Mary Plummer contributed to this report.