The doors to a previously hidden world of diplomatic intrigue and insults were dramatically thrown open last night as the whistle-blowing website Wikileaks published its vast tranche of secret American diplomatic communiqués. The release of hundreds of thousands of secret messages from staff at US embassies revealed how Washington has struggled to confront the geopolitical realities of a post-9/11 world.

It also exposed the often less than diplomatic language used by State Department insiders to describe some of the planet's most powerful leaders. Contained within the quarter of a million secret memos are revelations that:

*The Obama administration has ordered diplomats to gather vast amounts of personal, biometric and banking details about key global figures, including the United Nations Secretary-General, Ban Ki-moon;

*Key Arab allies in the Middle East, including King Abdullah of Saudi Arabia, have pleaded with Washington to take military action against Iran's nuclear programme;

*Tehran is thought to have obtained from North Korea a cache of Russian-designed missiles that could be fired at targets as far away as Berlin;

* US officials warned their German counterparts not to arrest CIA officers who were suspected by Berlin of being involved in America's "extraordinary rendition" programme – the secret global abduction and internment of suspected terrorists;

* Washington has grown increasingly wary of Italy's close ties to Russia, with one official describing Prime Minister Silvio Berlusconi as the "mouthpiece of [Vladimir] Putin" in Europe.

* Officials from the US Drug Enforcement Administration accused the Afghan Vice-President, Ahmad Zia Massoud, of travelling to the United Arab Emirates with $52m in cash;

The communiqués – most written between 2006 and 2009 – use colourful language to describe political leaders in ways bound to cause embarrassment in Washington and abroad. The Russian President, Dmitry Medvedev, is referred to as a "pale and apprehensive man", while Nicholas Sarkozy of France is "an emperor with no clothes" and Afghanistan's Hamid Karzai is "driven by paranoia".

Some of the harshest criticism is reserved for key anti-American leaders opponents. The Iranian President, Mahmoud Ahmadinejad, is described by one official as being "like Hitler", while North Korea's dictator Kim Jong-il is called a "flabby old man".

The German Chancellor, Angela Merkel, is praised as a strong US ally but dismissed as "risk-averse and rarely creative". Russia's Prime Minister Vladimir Putin, meanwhile, is derided as "an alpha dog" who plays Batman to Medvedev's Robin.

One of the most revealing personal details is the disclosure that the Libyan leader, Muammar Gaddafi, is accompanied at all times by a "voluptuous blonde" Ukrainian nurse.

There are also claims of "inappropriate behaviour" by an unnamed member of the British Royal Family.

Iran's nuclear programme surfaces frequently in the memos and is viewed as a key concern by the Americans and their Arab allies. Reports from US embassies in the Middle East suggest that King Abdullah of Saudi Arabia urged Washington to take military action against the Islamic republic and to "cut off the head of the snake". According to Wikileaks, leaders in Jordan and Bahrain also backed the use of armed force if necessary. One of the reports quotes Zeid Rifai, the then head of the Jordanian senate, telling a senior US official: "Bomb Iran, or live with an Iranian bomb. Sanctions, carrots, incentives won't matter."

A message dated 24 February this year says that US officials believe the Iranians have stockpiled 19 advanced BM-25 missiles, based on a Russian design, with help from North Korea. They are thought to have a range of 2,000 miles – 800 miles further than any missile Iran has had before. The Tehran regime is not yet thought to have the technology to build a nuclear warhead small enough to fit inside a BM-25, but the memos offer growing evidence that Tehran has the ballistic capability to target western Europe.

The messages also reveal some of the diplomatic pitfalls of America's so-called "war on terror". In 2007, the US fell out with Germany over arrest warrants that were issued for CIA agents accused of being involved in rendition. A senior US diplomat told a German official "our intention was not to threaten Germany, but rather to urge that the German government weigh carefully at every step of the way the implications for relations with the US".

There is also mounting concern about Pakistan's nuclear arsenal, which the US fears could be seized by Islamist militants. The leaked memos suggest that, since 2007, US officials have mounted a top secret but so far unsuccessful attempt to remove enriched uranium from a Pakistani research plant. In a message dated May 2009, the US ambassador, Anne W Patterson, says that Pakistan refused to grant American technicians access to the reactor because they feared that local media might get hold of the story and portray the visit as "the US taking Pakistan's nuclear weapons".

The cache of messages also casts aspersions upon the way US embassy staff are involved in collecting personal data about foreign nationals, blurring the line between standard diplomatic work and outright espionage. State Department personnel working at the UN, for example, were ordered in a July 2009 directive approved by Hillary Clinton to gather the credit card and frequent-flier details, work schedules, biometric data and other personal information about foreign dignitaries, including senior British representatives at the UN. They were also asked to collect details of "private VIP networks used for official communication, to include upgrades, security measures, passwords, personal encryption keys". Similar communiqués were sent to US staff in Burundi, Uganda, the Democratic Republic of Congo and Rwanda. One asked staff to acquire "internet and intranet 'handles', internet email addresses, website identification URLs; credit card account numbers; frequent-flier account numbers; work schedules and other relevant biographical information".

Classified State Department documents reveal that US embassy staff in Berlin recruited a German politician to supply them with confidential information about Chancellor Angela Merkel's coalition government shortly after it was elected in 2009.

Even though a significant number of the secret messages date back to before Mr Obama took office, the White House was aggressive yesterday in its condemnation of their release by Wikileaks, saying the publication could "deeply impact" US interests abroad and put lives "at risk".

Last night, the US ambassador to London, Louis Susman, said: "Releasing documents of this kind place at risk the lives of innocent individuals – from journalists to human rights activists and bloggers to soldiers and diplomats. It is reprehensible for any individual or organisation to attempt to gain notoriety at the expense of people who had every expectation of privacy in sharing information."

The founder of Wikileaks, Julian Assange, rejected the suggestion that the publication of the memos would endanger lives. "As far as we are aware, and as far as anyone has ever alleged in any credible manner whatsoever, no single individual has even come to harm as a result of anything we have ever published," said the 39-year-old Australian.

Despite Washington's fears that a vast amount of uncensored information was to be published by the website, Wikileaks went some way towards redacting the names of informants it believes might be persecuted.

What has been released?

* Most of the cables were written between 2006 and 2009 although a small number go back to the early 1990s.

* They are thought to have been downloaded from SPIR-Net, the Pentagon's global secret-level computer network, by Bradley Manning, a former Iraq-based army intelligence analyst.

* In total the cache comprises more than 251,000 documents, 11,000 of which are marked "secret". An additional 9,000 or so carry the label "noforn", meaning the information should not to be shared with those outside of the US, and 4,000 are marked "secret/noforn". The rest are either marked with the less restrictive label "confidential" or are unclassified.

* That such a large amount of confidential data can be so easily copied and leaked is testament to how the US government has struggled to combine better communication between its various government agencies and the need to protect secret information.