Yushchenko did not explicitly accuse the Russian government of involvement in his poisoning, but he did say he has "practically all the pieces put together" and that the attempt against his life was "not a private action."
Yushchenko fell gravely ill in September 2004 during his pro-Western campaign for the Ukrainian presidency.
He was rushed to a clinic in Vienna, where doctors determined he had ingested large quantities of the poison dioxin. Yushchenko survived and eventually returned to Kyiv -- his face horribly scarred by the poison -- to defeat pro-Moscow candidate Viktor Yanukovych in a late December rerun of the first vote, which was deemed to have been rigged. The rerun was ordered by the country's Supreme Court after weeks of Orange Revolution protests.
Now, Yushchenko is accusing Russia of blocking an investigation into who was behind the poisoning, and of harboring three key suspects in the case. No one has ever been charged.
In comments on September 11 to reporters in Dnipropetrovsk, in central Ukraine, Yushchenko said only three laboratories in the world produce dioxin, and that Ukraine has received samples from two of them.
"Analyses of dioxin have been made from all laboratories in the world, except those in Russia. I believe and hope that this research will also be done soon," Yushchenko said. "The three people needed most for the investigation are currently in Russia. All our requests to the prosecutor-general to have these people appear in Ukrainian courts have gone unanswered, including one in December that I personally handed over, requesting the help of Russian President Vladimir Putin."
Yushchenko said it is very easy to determine the origin of dioxin. The fact that Russia has not sent samples to be analyzed, he said, "limits the possibilities of the investigation."
He added that Moscow has a moral obligation to cooperate. "A country cannot let an attempt on anyone's life go unpunished, let alone on a presidential candidate. For both the country's honor and rule of law, the investigation must be completed and people have a right to know who committed the crime," Yushchenko said.
In separate newspaper interviews on Tuesday -- with "The Times" of London and the French daily "Le Figaro" -- Yushchenko stopped short of accusing Moscow of involvement, but said the attempt against his life was not the work of "private" individuals.
There has been no official reaction from the Kremlin to Yushchenko's statements. But Moscow's ambassador to Kyiv, Viktor Chernomyrdin, expressed surprise, saying he knows of no requests from Kyiv for assistance.
"Why are they making such accusations now, all of a sudden? They should have asked and talked to us. But who did they ask, who did they talk to? I have no idea, I've been here all the time and I have met the [Ukrainian] president many times and not only him, but also others, and it is the first time I've heard that he made such a request to the [Russian] president himself," Chernomyrdin said.
Russian political analyst Sergei Markov, who has close ties to the Kremlin, told RFE/RL's Ukrainian Service that Yushchenko's allegations reflect nothing more than a deep-seated resentment toward Russia.
"Yushchenko is a Russophobe in his views. He hates Russia and Russians. He is trying to find a pretext for accusing Russia of something," Markov said. He continued: "Yushchenko is jumping to take advantage of the accusations made in Great Britain and other countries that Russia is hindering court investigations into murders and poisonings -- in particular, the accusation that Russia is hindering the investigation into [former security officer Aleksandr] Litvinenko's poisoning. He's simply making use of this pattern."
It is unclear why the Ukrainian president waited three years to level such an accusation. Ukrainian political expert Kost Bondarenko suggests such claims -- about Yushchenko's poisoning and other high-profile criminal cases -- may be seen as useful PR for Yushchenko and his Our Ukraine bloc ahead of Ukraine's September 30 parliamentary elections.
"These are absolutely groundless accusations. As early as two years ago, Yuriy Lutsenko, who was then [Ukrainian] interior minister, announced that the [poisoning] case had actually been solved and that he knew all the perpetrators," Bondarenko said. "They are now trying to find a way out of this situation." He added that people are increasingly seeking answers not only to the Yushchenko poisoning, but also to the unsolved murders of Ukrainian journalist Heorhiy Gongadze in 2000 and former National Bank governor Vadym Hetman in 1998.
Yushchenko's physical appearance has markedly improved since the poisoning. His face is still pockmarked but his skin seems to have healed considerably and no longer has a grayish-green hue. Describing his recovery to reporters in Dnipropetrovsk, Yushchenko said, "Given what has happened over the past three years, I have not really told anyone how difficult it has been for me simply to get up each morning, or for how many months I have no longer been taking pain-killers and antibiotics -- in short, the price I paid to remain among you."
Yushchenko has had to undergo regular treatment at a Swiss clinic to remove the dioxin from his body.