Government

Reuters) - U.S. authorities could face insurmountable legal hurdles if they try to bring criminal charges against elusive WikiLeaks chief Julian Assange, even if he sets foot on U.S. soil.

The Justice Department is investigating a series of leaks of hundreds of thousands of classified U.S. documents that the whistleblower website has provided to news media and made public on its own website.

But three specialists in espionage law said prosecuting someone like Assange on those charges would require evidence the defendant was not only in contact with representatives of a foreign power but also intended to provide them with secrets.

No such evidence has surfaced, or has even been alleged, in the case of WikiLeaks or Assange, an Australian-born former computer hacker who has become an international celebrity.

Mark Zaid, a defense lawyer who specializes in intelligence cases, said it would be "very difficult for the U.S. government to prosecute (Assange) in the U.S. for what he is doing."

Assange, who leads a nomadic existence and cultivates an aura of mystery, left Sweden last month after authorities there said they wanted to question him about allegations of rape and other sexual offenses.

Interpol, the international police agency, issued a "red notice" on Tuesday to assist in his arrest over the Swedish investigation. Assange has said the allegations are baseless and criticized what he calls a legal circus in Sweden.

While his current whereabouts are not known, it appeared briefly that Assange could find a home in South America.

Ecuador's deputy foreign minister said the government was trying to invite him to live and lecture there. But President Rafael Correa quickly canceled the invitation, saying WikiLeaks "has committed an error by breaking the laws of the United States and leaking this type of information."

Other parts of U.S. law make it easier to prosecute people for unauthorized disclosures of undercover U.S. intelligence officers'...