Almost a decade after former KGB agent and British citizen Alexander Litvinenko's painful death and burial in a lead-lined coffin, his deathbed accusation that the Russian state was responsible appears to have been officially vindicated, as the final report of the inquiry into his death was published on Thursday.

The 328-page report said there was a "strong probability" the Russian intelligence agency (FSB) directed two men to poison Litvinenko in London, and that this operation was "probably" sanctioned by then FSB head Nikolai Patrushev and Russian President Vladimir Putin.

It also ruled out suicide, accidental poisoning, or a "set-up" as the cause of Litvinenko's death, and said that Andrei Lugovoi and Dmitry Kovtun — the main suspects — were definitely responsible for killing him. It found that Litvinenko was poisoned twice, and that the fatal dose of radioactive polonium 210 was administered in the Pine Bar in London's Millennium Hotel on November 1, 2006.

It ruled that Lugovoi and Kovtun had no personal gripe against Litvinenko, and must have killed him on behalf of others. "The fact that Mr. Litvinenko was poisoned with polonium 210 that had been manufactured in a nuclear reactor suggests that Mr. Lugovoi and Mr. Kovtun were acting for a state, rather than (say) a criminal organization," it said.

It found that the Russian state had reasons for wanting him dead, and said there was "undoubtedly a personal dimension to the antagonism between" Litvinenko and Putin. It concluded: "The FSB operation to kill Mr. Litvinenko was probably approved by Mr. Patrushev and also by President Putin."

The report also said the state honor awarded to Lugovoi in March 2015 — while the inquiry was ongoing — could be only interpreted as "a deliberate sign of public support made to him by President Putin," and showed the Russian state approved of Litvinenko's killing, "or at least that it wishes to signal approval for it."

Page 178 of the report showing an analysis of the teapot that contained the radioactive polonium. (Photo by Sally Hayden/VICE News)

The final document was delivered to the British Home Secretary on Tuesday, but its contents remained shrouded in secrecy until today.

Speaking on Thursday after the report's publication, Litvinenko's widow Marina said: "I am of course very pleased that the words my husband spoke on his death bed when he accused Mr. Putin of his murder have been proved true in an English court with the highest standards of independence and fairness."

Now, she continued, she's calling for targeted economic sanctions against named individuals, including Putin and Patrushev, as well as the expulsion of all Russian intelligence operatives from the UK. Marina also said she had received a letter from Home Secretary Theresa May, who had promised further action.

Giving a statement to the House of Commons soon afterwards, May said the UK was going to impose asset freezes on both Kovtun and Lugovoi. International arrest warrants for them remain in place, she added, while calling the murder a "blatant and unacceptable breach of the most fundamental tenets of international law and civilised behaviour."

The UK's Metropolitan Police also released a statement, saying they will be considering the content of this report and its conclusions carefully. Commander Duncan Ball, who led the police investigation, said it had been "a painstaking and meticulous enquiry."

"It is important to remember that behind the significant global interest in this case, this remains an investigation into the murder of a man on the streets of London," he said. "Marina and Anatoly Litvinenko have shown immense courage and dignity since Alexander's death and with them, we remain committed to bringing those responsible to justice."

Page 201 of the report shows a t-shirt sent to exiled Russian oligarch Boris Berezovsky in July 2010, apparently by Lugovoi.

Meanwhile, Russia's Foreign Ministry has dismissed the inquiry, saying it was not impartial and the conclusions were pre-determined.

In a statement, Maria Zhakarova, director of the ministry's press services, said: "We regret that a purely criminal case has been politicized and has darkened the general atmosphere of bilateral relations."

Zhakarova also said the decision to hold the inquiry was "politically motivated."

In a statement released after he was summoned to the Foreign Office today, Russian ambassador Alexander Yakovenko called the inquiry's report "unacceptable" and said Russia would "never accept anything arrived at in secret and based on the evidence not tested in an open court of law."

"This gross provocation of the British authorities cannot help hurting our bilateral relationship," he said, adding that the delay in reaching conclusions led Russia to believe this was "a whitewash of British security services incompetence."

Lugovoi and Kovtun have also repeatedly denied the charges against them.

The inquiry took place between January and July this year. It included of 34 days of hearings, 62 oral testimonies, a mass of documents, and written evidence from a significant number of further witnesses.

A statement made by Litvinenko before he died was read out by his friend Alex Goldfarb outside University College Hospital, London. In it he accused Russian President Vladimir Putin of involvement in his death and said his killer was "barbaric and ruthless".

Protest from around the world "will reverberate, Mr. Putin, in your ears for the rest of your life," the statement said.