Whistle-blowing website WikiLeaks has released 250,000 secret messages sent by United States embassies.
They include a US diplomatic cable reporting the frequent exhortations of the King of Saudi Arabia to the US to attack Iran, the BBC reports.
The documents carry reports of other Arab leaders telling the Americans to terminate Iran's nuclear weapons programme by whatever means necessary.
Other concerns include the security of Pakistani nuclear material that could be used to make an atomic weapon.
The widespread use of hacking by the Chinese government targeting the US and its allies is also reported.
WikiLeaks founder Julian Assange said the US authorities were afraid of being held to account.
But the White House said the release was "reckless" and put the lives of diplomats and others at risk.
Republican congressman Peter King called for WikiLeaks to be designated a terrorist organisation.
The Pentagon condemned the "reckless" release of classified US State Department documents and said it was taking steps to bolster security of classified US military networks, Reuters reports.
The leaked cables by US diplomats posted overseas contain blunt appraisals of their host governments, and unflattering pen portraits of world leaders.
Documents from US officials in Australia
The ABC reports a number of the documents have been written by US officials in Australia.
It appears about 930 documents have come from the American embassy in Canberra, but it is not yet clear what information is revealed.
Earlier, WikiLeaks said it had come under attack from a computer-hacking operation.
The website has previously released secretary US military papers about the war in Afghanistan and US military operations in Iraq.