The widow of Alexander Litvinenko said that leaked US diplomatic cables vindicated her long-standing claim that Vladimir Putin had authorised her husband's murder.

In secret conversations with the French, the top US diplomat Daniel Fried said it was unlikely Putin was not aware of the operation to poison Litvinenko with polonium, "given Putin's attention to detail".

Fried also dismissed the idea that rogue criminal elements were to blame. The Russians were behaving with "increasing self-confidence to the point of arrogance", he added, in a classified cable revealed yesterday.

In a statement to the Guardian today, Marina Litvinenko said the cable – written two weeks after her husband's death in November 2006 – confirmed her assertion this was a Kremlin-authorised operation.

She said: "There is some satisfaction in seeing what we have all known to be true documented so officially, and I would add brutally by being so matter of fact in its description. It brings me a little closer to achieving truth and justice for my late husband.

"For years we have been trying to get the authorities in the west to view my husband's murder as a state-sponsored crime. Now it appears they knew it all along."

Marina Litvinenko recalled that while dying her husband had accused Putin of the poisoning, calling it "Vladimir Putin's work".

"Now the whole world knows and can see the truth through the leaking of these official US documents,' she said.

Ahead of Fifa's decision to award Russia the 2018 World Cup, Putin's press spokesman today accused US diplomats of having "a perverted understanding of reality".

Dmitry Peskov said that the American officials stationed in Moscow who described Russia as a kleptocracy had failed to grasp the reality of the country. "It's extremely striking that there are diplomats here having such a perverted understanding of reality. It's ignorance ... it's something beyond understanding," he told the BBC.

The Russian foreign ministry said the cables published by WikiLeaks yesterday aroused bewilderment and regret in Russia – but contained no great surprises.

"In our work we are regularly confronted with stereotypes," said a spokesman, Alexei Sazonov, adding that most of the cables were little more than "routine diplomatic correspondence"' between the US state department and its embassies, and would not affect "positive developments" in US-Russian relations. "As for comments on specific subjects, I cannot and will not make any," he said.

The revelations in the cables were made by successive ambassadors in Moscow and published in the Guardian. The blunt reports disclosed by WikiLeaks conclude that Russia is a criminal state dominated by venal and bribe-hungry officials.

Yet, while details of the cables spread quickly through websites and the blogosphere in Russia, television – from which an estimated 70% of Russians get their news – ignored the reports. State-controlled Rossiya made no mention of the allegations in its mid-morning news broadcast Instead, it reported on the Moscow river freezing over, on two Russian tourists being attacked by sharks in Egypt, and on government-employed truck drivers in the US who got drunk while transporting nuclear weapons.

The news agency Interfax did publish extracts from cables alleging that Moscow's recently sacked mayor Yuri Luzhkov presided over a "pyramid of corruption". But Interfax – and other media outlets – remained mute over claims that Putin had "illicit proceeds" from abroad and had amassed a secret fortune.

One Kremlin expert queried the timing of the disclosures and accused this newspaper of plotting to wreck Russia's bid for the 2018 World Cup: "You have to immediately ask how does this benefit the Guardian?"

Dmitry Badovsky, deputy director of the Social Systems Research Institute, told the state news agency Ria Novosti. "You can make several guesses. Why does this information appear on the eve of the choice of which country will host the 2018 World Cup, and in which England and Russia are leading rivals."

Russian state television did give over a large segment to Larry King's interview with Putin, shown last night on CNN.

Asked by King for his response to the assessment of the US defence secretary, Robert Gates – revealed earlier by WikiLeaks – that "Russian democracy has disappeared and that the government is being run by the security services," Putin replied: "I am personally acquainted with Mr Gates, I have met him on several occasions. I think he is a very nice man and not a bad specialist. But Mr Gates, of course, was one of the leaders of the US Central Intelligence Agency and today he is defence secretary. If he also happens to be America's leading expert on democracy, I congratulate you."

King also asked about the 10 Russian "sleeper agents" caught in the US in June and later deported to Moscow. Putin claimed that they had not harmed US interests, adding: "The methods employed by our special services differ in a good way from those used by US special services. Thank God, neither the agents in question or any other Russian intelligence officers are known to have been involved in creating secret prisons, kidnappings, or torture."

The prime minister also warned that Moscow must agree partnership with Washington over a joint missile defence shield. If not, he said, "Russia will just have to protect itself using various means, including the deployment of new missile systems to counter the new threats to our borders, and the development of new nuclear-missile technology." Putin added: "We don't want this. It's not a threat. We are simply talking about what to expect if we can't agree to work together."

The Kommersant newspaper said this morning that Putin's comments showed "Russo-American relations are returning to the rhetoric of the cold war."