Confidential memos, most of which date from 2007 to February of this year, recount closed-door remarks.
The Whistleblower website released some 250,000 U.S. diplomatic cables.
The documents reveal, among other things, how the State Department ordered diplomats to spy on foreign officials.
Whistleblower website WikiLeaks has unleashed a flood of U.S. cables detailing shocking diplomatic episodes, from a nuclear standoff with Pakistan to Arab leaders urging a strike on Iran.
The leaked memos describe a Chinese government bid to hack into Google; plans to reunite the Korean peninsula after the North's eventual collapse; Saudi Arabia's king's call to the United States to bomb Iran to halt its nuclear drive.
The documents also showed that Israel discussed its planned war on Gaza with the Palestinian leadership and Egypt ahead of time, offering to hand them control of the strip, if it defeated Hamas.
The confidential cables, most of which date from 2007 to February this year, also reveal how the State Department has ordered diplomats to spy on foreign officials and even to obtain their credit card and frequent flier numbers.
The memos, released on Sunday, recount closed-door remarks such as Yemen's president telling a top U.S. general: "We'll continue saying the bombs are ours, not yours" when discussing secretive US strikes on Al-Qaeda.
A description of Libyan leader Moamer Kadhafi said he required the near-constant assistance of a "voluptuous blond" Ukrainian nurse.
The Guardian newspaper reported that a classified directive sent to U.S. diplomats under U.S. Secretary of State Hillary Clinton's name in July 2009 sought technical details about the communications systems used by top U.N. officials.