More than a quarter of a million classified cables sent from U.S. embassies around the world to Washington have been leaked on the Internet. Despite warnings from the U.S. government that the leaks could put lives at risk, the website WikiLeaks published the files in conjunction with several major international newspapers.

According to The New York Times and several European newspapers, the leaked messages are described as varying between embarrassing and highly damaging, with the potential to adversely affect U.S. relations with several countries.

Among the most striking, according to the papers, are leaked cables suggesting that Saudi Arabia and other Arab countries have been pressing the U.S. government to launch a military attack on Iran to prevent the country from developing a nuclear weapon. An apparent message from April 2008 suggests that King Abdullah of Saudi Arabia called for the United States to "Cut the head off the snake."

Other documents reportedly suggest that the United States believes that Saudi Arabian donors are the chief financiers of terror groups like al-Qaida. Qatar, a U.S. ally, is accused of not doing enough to thwart terrorist groups.

It is also alleged that Iran has received sophisticated missiles from North Korea that are capable of hitting Western Europe and that it is using them to construct even bigger weapons.

According to newspaper reports, more than 4,000 files are marked "No Foreigner." These include cables alleging that the U.S. military has been conducting air strikes against al-Qaida targets in Yemen. The Yemeni government has said that its military alone has been conducting the raids.

Chinese government operatives reportedly are accused of launching cyber attacks on the United States.

The messages are also said show that U.S. Secretary of State Hillary Clinton urged American diplomats to spy on other countries at the United Nations - blurring the traditional boundaries between diplomacy and espionage.

Among the more embarrassing leaks, say the newspapers, are personal analyses of world leaders. Former Russian President Vladimir Putin reportedly was called an "alpha-dog" and Afghan President Hamid Karzai is said to have been described as "driven by paranoia." The reports also say the cables noted that Libyan leader Moammar Gadhafi is permanently accompanied by a "voluptuous Ukrainian nurse." One message apparently accused an unnamed member of the British royal family of "inappropriate behavior."

The Pentagon has declined to comment on the contents of the leaked documents. But it has condemned the leaks as reckless, warning that their publication would place at risk "the lives of countless innocent individuals," "ongoing military operations" and "cooperation between countries."

Speaking on the "Fox News Sunday" television program, Democratic U.S. Senator Claire McCaskill called for WikiLeaks to be prosecuted. "The people who are leaking these documents need to do a gut check about their patriotism. And I think they're enjoying the attention that they're getting. But frankly, it's coming at a very high price. I hope we can figure out where this is coming from and go after them with the force of law," she said.

Republican Representative Peter King, who is a member of the House of Representatives Committee on Homeland Security, has called for WikiLeaks to be classified as a terrorist organization.

No one has been charged with disclosing information to WikiLeaks, but news reports say a key suspect is U.S. Army private Bradley Manning, who is in custody for an earlier leak of classified documents.

The Pentagon says it is in the process of increasing security measures for its data and communications.