Assange returns as US insists his actions risked lives

The US State Department says its involvement in the resolution of Julian Assange's case was very limited but a department representative has reiterated the US government's position that the WikiLeaks founder's actions had put lives at risk.

The State Department spokesperson was asked by reporters at a press briefing on Wednesday to give examples of harm caused by the WikiLeaks releases but did not provide any.

Assange landed to an ecstatic welcome at Canberra Airport on Wednesday evening after pleading guilty to violating US espionage law in a deal that sets him free from a 14-year legal battle.

Chief US District Judge Ramona V Manglona in the US territory of Saipan accepted Assange's guilty plea on Wednesday.

Assange had agreed to plead guilty to a single criminal count, according to filings in the US District Court for the Northern Mariana Islands.

While the US has often called Assange's actions reckless and claimed they put its agents at risk of harm, the judge noted on Wednesday that the United States could not identify any personal victim from them.

Assange's supporters say he is a hero who was victimised because he exposed US wrongdoing and alleged war crimes, including in conflicts in Afghanistan and Iraq in the 2010 publications of documents.

"The State Department did an extraordinary amount of work when we found out that these cables were going to be published to get people out of harm's way ... and take action so people that would be put in danger would be put out of harm's way," the spokesperson said.

The State Department said the US Justice Department acted independently in the case and did not face interference from other agencies.

The spokesperson added that there was some limited co-ordination between the US State Department and the Australian government recently in relation to the case.

Australia had been advocating for the release of Assange, an Australian citizen.

"We have an independent Justice Department," the State Department spokesperson said.

"There was some small co-ordination role between our embassy and the Australian government in the last few days."

It is unclear where Assange will go from Canberra and what his future plans are.

His South African-born lawyer wife and mother of his two children, Stella Assange, has been in Australia for days awaiting his release.

Another of Julian Assange's lawyers, Barry Pollack, expected his client would continue vocal campaigning.

"WikiLeaks's work will continue and Mr Assange, I have no doubt, will be a continuing force for freedom of speech and transparency in government," Pollack said.

Assange's father John Shipton said ahead of his son's arrival that he hoped that his first-born child was coming home to the "great beauty of ordinary life".

"He will be able to spend quality time with his wife Stella and his two children, be able to walk up and down the beach and feel the sand through his toes in winter, that lovely chill," Shipton said.

The plea deal required Assange to admit guilt to a single felony count but also permitted him to return to Australia without any time in a United States prison.

The judge sentenced him to the five years he'd already spent behind bars in the United Kingdom fighting extradition to the US on an Espionage Act indictment that could have carried a lengthy prison sentence in the event of a conviction.

He was holed up for seven years before that in the Ecuadorian embassy in London.

The conclusion enables both sides to claim a degree of satisfaction.

The Justice Department, facing a defendant who had already served substantial jail time, was able to resolve - without trial - a case that raised thorny legal issues and that might never have reached a jury at all given the plodding pace of the extradition process.

Assange, for his part, signalled a begrudging contentment with the resolution, saying in court that although he believed the Espionage Act contradicted the First Amendment, he accepted the consequences of soliciting classified information from sources for publication.

Assange on Monday had left the London prison where he has spent the last five years after being granted bail during a secret hearing last week.

Assange's bail hearing was requested to be heard in secret as his plea agreement was "confidential and sensitive in terms of national security for the US," a UK judicial spokesperson said.

A plea agreement was signed on June 19 and the bail hearing was heard in private on the next day at Westminster Magistrates' Court.

with AP and PA