Silvio Berlusconi is "feckless, vain and ineffective" while Dmitry Medvedev is "Robin to Putin's Batman", according to secret memos sent by diplomats.
Among hundreds of thousands of documents released on Sunday night by Wikileaks, the whistle-blower website, are US embassy cables detailing private impressions of a host of world leaders written by ambassadors and ministers across the globe.
Here is a round-up of what the documents say about some of the world's most influential figures, as reported by the newspapers given advanced access to the material; The New York Times, The Guardian, Der Spiegel, Le Monde and El Pais.
Muammar Gaddafi, Libyan leader
Gaddafi "cannot travel" without what one diplomat described as his “voluptuous blonde” Ukrainian nurse.
The report, from the US embassy in Tripoli, disclosed that Colonel Gaddafi appeared to be afraid of staying on upper floors and disliked flying over water.
He enjoyed horse racing and flamenco dancing and was upset when he was refused permission to pitch his Bedouin tent in New York City.
Dmitry Medvedev, Russian President
Medvedev is officially the senior partner to Vladimir Putin in the Russian government, but American documents painted the balance of power in Moscow as quite different.
According to one diplomat's cable in late 2008, shortly after Medvedev assumed power, Mr Putin behaves like “Batman” while Medvedev “plays Robin”.
Vladimir Putin, Russian Prime Minister
Vladimir Putin was described as "alpha dog", while diplomats suggested his macho and authoritative image had helped him develop a “remarkably close” relationship with his Italian counterpart, Silvio Berlusconi.
The pair reportedly exchanged “lavish gifts” and US officials were concerned that Berlusconi was becoming “the mouthpiece of Putin” in Europe.
Silvio Berlusconi, Italian Prime Minister
Mr Berlusconi was described as “physically and politically weak” at home, and “feckless, vain, and ineffective” European leader.
His “frequent late nights and penchant for partying hard mean he does not get sufficient rest", one observed.
US diplomats in Rome also raised concerns over contracts between Italy and Russia and a “shadowy” Russian-speaking Italian who acted as a go-between.
Nicholas Sarkozy, French President
The French President was referred to as an “emperor with no clothes” in an American memo.
The diminutive leader was seen as “thin-skinned”, and “authoritarian” in his personal style, with a tendency to rebuke his senior team repeatedly for their alleged shortcomings, according to the US embassy in Paris.
Angela Merkel, German Chancellor
A leaked American cable claimed that Merkel “avoids risks and is rarely creative”. She was also repeatedly referred to as Angela “Teflon” Merkel because nothing sticks to her.
Memos betray the American perception that Merkel approaches international relations with the aim of making as much domestic profit as possible.
Hamid Karzai, Afghan president
Mr Karzai was painted as paranoid and feeble in a dispatch from Kabul.
It portrayed Karzai as “an extremely weak man who did not listen to facts but was instead easily swayed by anyone who came to report even the most bizarre stories or plots against him”.
Mahmoud Ahmadinejad, Iranian President
Concerns over Iran were a major theme in the cables, one of which compared the Iranian President, Mahmoud Ahmadinejad, to Adolf Hitler.
The documents report that King Abdullah of Saudi Arabia repeatedly urged America to take military action against Iran so as to destroy its nuclear programme and “cut the head off the snake”.
Robert Mugabe, Zimbabwean President
The controversial Zimbabwean leader was caricatured as “the crazy old man” by a minister in the South African government, according to a US report from Pretoria.
A dispatch from the embassy in Harare entitled “The End is Nigh” describes Mugabe as “ruthless” and “a brilliant tactician”, but adds that he is hampered by “his ego and his belief in his own infallibility”.
Kim Jong-il, North Korean leader
The ailing dictator of North Korea was portrayed as a “flabby old chap” who had suffered “physical and psychological trauma” as a result of his stroke.
Documents also disclose that American and South Korean officials have discussed the potential for a unified Korean nation, in the event the North were to collapse.
Ali Abdullah Saleh, Yemeni President
The leader of Yemen was viewed by diplomats as “dismissive, bored and impatient” during a meeting he held with John Brennan, a senior adviser to the US President on national security.
In a meeting with General David Petraeus, the former American commander in the Middle East, Saleh reportedly said: “We’ll continue saying the bombs are ours, not yours”.