Col. Denise Lind, who presided over the court-martial at Fort Meade, Md., found Manning guilty of several violations of the Espionage Act Tuesday. The sentencing phase begins Wednesday.
Press freedom advocates said the verdict adds to their concerns about President Obama's administration's hard-line pursuit of leakers, saying the convictions will discourage whistle-blowers from providing critical military and intelligence information, The Washington Post reported Tuesday.
Even though defense attorneys denied the claim that Manning was being directed by WikiLeaks and Assange, government prosecutors "kept trying to bring that up, trying to essentially say that Julian was a co-conspirator," said Michael Ratner, Assange's U.S. attorney.
"That's a very bad sign about what the U.S. government wants to do to Julian Assange," Ratner said.
Assange has been living in the Ecuadoran Embassy in London for more than a year after he exhausted his appeals fighting extradition to Sweden for questioning in a sexual assault case. Assange has said he feared he would be sent to the United States if he were returned to Sweden.
There is a grand jury investigation into WikiLeaks, a spokesman for the U.S. Attorney's Office for the Eastern District of Virginia told the Post. It is unclear, however, whether there are sealed indictments or if Assange has been charged.
"Either there [are] charges already, which I think is very possible, or they now have this and they can say they have one part of the conspiracy," Ratner said.
Trevor Timm, executive director of the Freedom of the Press Foundation, also predicted Manning's convictions brought Assange "one step closer" to prosecution. But, he added, "charging a publisher of information under the Espionage Act would be completely unprecedented and put every decent national security reporter in America at risk of jail, because they also regularly publish national security information."
Assange called Manning's conviction "a dangerous precedent," saying Manning represents "the quintessential whistle-blower," Politico reported.
"Bradley Manning's alleged disclosures have exposed war crimes, sparked revolutions, and induced democratic reform," Assange said in a statement Tuesday. "This is the first ever espionage conviction against a whistle-blower. It is a dangerous precedent and an example of national security extremism. It is a short-sighted judgment that cannot be tolerated and must be reversed. It can never be that conveying true information to the public is 'espionage.'"