Among the sensational revelations are claims that Arab states privately want the United States to attack Iran and that the Americans are planning to spy on U.N. leaders, reported The Guardian, one of the media outlets that received the cables.
On another highly sensitive issue revealed in the cables, the United States has been trying to remove highly enriched uranium from a Pakistani research reactor, The New York Times reported.
In May 2009, Ambassador Anne Patterson reported Pakistan was refusing a visit by American experts because it could be portrayed as the United States taking Pakistan's nuclear weapons.
According to Der Spiegel, another recipient of the leaks, a State Department official said President Barack Obama "prefers to look East rather than West," and "has no feelings for Europe."
Relations with one of the closest U.S. allies, Britain, may be damaged by criticisms of Prime Minister David Cameron and requests for specific intelligence about individual Parliament members, The Guardian said.
There are also charges of inappropriate behavior by a member of the royal family.
The cables also reveal U.S. offers to several countries of favors or aid in return for taking Guantanamo Bay prisoners and discussion of scenarios for a collapse of North Korea and China's reaction, the Times said.
Secretary of State Hillary Clinton spent the weekend trying to contain the damage, The Guardian said, calling leaders in Germany, Saudi Arabia, the Persian Gulf, France and Afghanistan.
U.S. ambassadors were briefing their host country leaders in advance of the embarrassing revelations. It will be hard to convince contacts around the world that future conversations will be kept secret.
State Department legal adviser Harold Hongju Koh sent a letter to WikiLeaks founder Julian Assange and his lawyer in London Saturday, CNN and The Washington Post reported.
"If any of the materials you intend to publish were provided by any government officials, or any intermediary without proper authorization, they were provided in violation of U.S. law and without regard for the grave consequences of this action," the letter said. "As long as WikiLeaks holds such material, the violation of the law is ongoing."