A large batch of U.S. diplomatic messages obtained by WikiLeaks and given to several media outlets reveals frank and sometimes unflattering assessments of several world leaders.

Details of the latest WikiLeaks dump appeared Sunday in publications that included the weekly German magazine Der Spiegel, the French newspaper Le Monde, the New York Times, England's Guardian newspaper and the Spanish newspaper El Pais.

The whistleblower website gave them access to a cache of 250,000 documents.

More files were expected to be released throughout the week, following the initial publication.

According to Der Spiegel, Iranian President Mahmoud Ahmadinejad is compared to Hitler in U.S. diplomatic files.

Other documents show that Israel expressed concerns about Iran's expanding nuclear program, while King Abdullah of Saudi Arabia urged the U.S. to help the kingdom erode Iran's influence in Iraq, the New York Times said.

French President Nicolas Sarkozy was nicknamed "the emperor with no clothes" and Afghanistan President Hamid Karzai is described as "driven by paranoia."

Diplomats talked of Italian Prime Minister Silvio Berlusconi as liking "wild parties" and described Russian Prime Minister Vladimir Putin as an "alpha dog."

German Chancellor Angela Merkel is praised as "Teflon."

Christopher Dell, who spent three years as ambassador to Zimbabwe, calls Robert Mugabe, the African country's president, "a brilliant tactician" but mocked "his deep ignorance on economic issues."

The New York Times said the files cover three years of communications between U.S. diplomats and Washington and some are dated as recently as late February.

The publications have, for weeks, been reading and analyzing the files.

The cables (messages) were exchanged via the huge Secret Internet Protocol Router Network, or SIPRNet. It has been described as a worldwide U.S. military internet system, kept separate from the ordinary civilian internet and run by the U.S. defence department in Washington.

WikiLeaks has distributed two other large batches of classified files since July. Those involved U.S. military reports on the wars in Afghanistan and Iraq.

'Irresponsible leaks like these are deplorable and do not serve anybody's national interests.'—Foreign Affairs Minister Lawrence Cannon

The United States had warned WikiLeaks editor in chief Julian Assange that distributing the latest round of documents would endanger peoples' lives.

"As we have in the past, we condemn this reckless disclosure of classified information illegally obtained," the Pentagon said in a statement Sunday.

The Pentagon also said it has toughened security procedures to prevent future leaks of sensitive material.

Pentagon spokesman Bryan Whitman said since August, the Pentagon has changed its rules for using flash drives or similar storage devices. It has also changed the way classified material is moved into unclassified computer systems.

Canadian Foreign Affairs Minister Lawrence Cannon joined the U.S. in condemning the documents' release.

"Irresponsible leaks like these are deplorable and do not serve anybody's national interests. The perpetrators of these leaks may threaten our national security," Cannon said.

U.S. diplomats made note of Canada's stand against Libyan leader Moammar Gadhafi in the fall of 2009.

Gadhafi cancelled a planned stopover in St. John's after learning Cannon wanted to meet him at the airport and express Canada's displeasure over the hero's welcome Libya had given to the man convicted of the 1988 Lockerbie bombing.

The leaked files also reveal that Gadhafi's dislike of long flights and apparent fear of flying over water caused logistical headaches for his staff.

At the time of the Canadian snub, the Libyan leader was booked to fly home from New York City, where he had addressed the UN General Assembly.