Australia's foreign minister said on Wednesday that the US government is responsible for the leaking of hundreds of thousands of classified diplomatic memos, and cautioned against blaming the website that published the secret cables and its founder.

US Secretary of State Hillary Rodham Clinton and other American officials have said that WikiLeaks acted illegally when it posted the sensitive files — memos from American embassies around the world that have embarrassed Washington.

The US government is investigating whether Julian Assange, the website's Australian founder, can be prosecuted for espionage or other offenses.

But Kevin Rudd said the blame lies with the leaker and the US government's failure to protect its secrets. "The bottom line here is that the core of all this lies with the failure of the government of the United States to properly protect its own diplomatic communications," Rudd told Melbourne Talk Radio on Wednesday.

If Assange, who has been arrested and jailed in London in an unrelated sex-crimes investigation, is also going to be pursued, he must be presumed innocent, Rudd said.

"To have several million people on their distribution list for a quarter of million cables — that's where the problem lies and the person or persons responsible for their unauthorized release, who then gets engaged in the business of disseminating the content of that information, be it WikiLeaks, or anybody else, well that's a matter to be tested by the police," Rudd said.

Assange surrendered to British police Tuesday to answer an arrest warrant issued for his arrest in Sweden. He is wanted for questioning after two women accused him of having sex with them without their consent. Rudd said that Australia would support Assange, as it would any Australian arrested abroad.

Assange defended his website in an opinion piece published in an Australian newspaper on Wednesday.

The 39-year-old writes in the opinion piece, published by The Australian, that there is a great need for WikiLeaks and denies that the site's publication of classified information has endangered lives — a claim made last week by former US President Bill Clinton.

"WikiLeaks has a four-year publishing history. During that time we have changed whole governments, but not a single person, as far as anyone is aware, has been harmed," Assange wrote. "But the US, with Australian government connivance, has killed thousands in the past few months alone."

He wrote that democracies require strong media to keep governments honest and that WikiLeaks helps fulfill that role. "WikiLeaks has revealed some hard truths about the Iraq and Afghan wars, and broken stories about corporate corruption."