VIENNA, Austria -- Ukrainian presidential candidate Viktor Yushchenko was poisoned with dioxin, doctors said Saturday, adding that the highly toxic chemical could have been put in the opposition leader's soup, producing the severe disfigurement and partial paralysis of his face.
Yushchenko was in satisfactory condition and was expected to be released from Vienna's private Rudolfinerhaus clinic today or Monday to return to the campaign trail in Ukraine, said hospital director Dr. Michael Zimpfer.
Yushchenko, who faces Viktor Yanukovych in a rerun of a disputed presidential runoff on Dec. 26, has claimed that he was poisoned by Ukrainian authorities, who deny the charges. His supporters at home expressed little surprise over the doctors' conclusion.
"Everybody knew he was poisoned so we didn't really need official tests," said Anatoly Klotchyk, 19, standing in the sleet outside his tent near Kiev's Independence Square, where supporters have conducted a blockaded of government buildings since the dispute flared, grabbing international attention after the runoff last month.
Campaigners for his opponent, Viktor Yanukovych, meanwhile, again rejected suggestions that the prime minister was involved in the poisoning.
There is "no logic in such an accusation," said Taras Chornovyl, Yanukovych's campaign manager.
Yanukovych was declared the winner of the Nov. 21 presidential runoff, but the results were annulled by the Ukrainian Supreme Court, which cited massive fraud and ordered a new vote.
Yushchenko fell ill in early September and had been treated at the Vienna clinic twice before. But it was the tests run since he checked in Friday night that provided conclusive evidence of the poisoning, Zimpfer said.
The 50-year-old politician also has suffered from back pain and acute pancreatitis.
"There is no doubt about the fact that Mr. Yushchenko's disease -- especially following the results of the blood work -- has been caused by a case of poisoning by dioxin," Zimpfer said.
"We suspect involvement of an external party, but we cannot answer as to who cooked what or who was with him while he ate," Zimpfer said, adding that tests showed the dioxin was taken orally.
Zimpfer said Yushchenko's blood and tissue registered concentrations of dioxin -- one of the most toxic chemicals -- that were 1,000 times above normal levels.
"It would be quite easy to administer this amount in a soup," Zimpfer said.
The substance containing the dioxin would most likely have been consumed the day Yushchenko fell ill, as dioxin is rapidly absorbed, Zimpfer said.
"This substance led to quite a significant increase in the (dioxin) level within just a few hours and this intake then led to the quite devastating effects that we have seen," he said. "The substance started to wreak havoc in the body."
A parliamentary commission that investigated Yushchenko's mysterious illness in October said he complained of pains after meeting with Ihor Smeshko, the head of Ukraine's Secret Service, but it lists other places he ate or drank that day. Smeshko promised the secret service would investigate.
The massive quantities of dioxin in Yushchenko's system caused chloracne, a type of adult acne produced by exposure to toxic chemicals that left his once-handsome face badly disfigured, hospital dermatologist Hubert Pehmberger told The Associated Press.
Chloracne can take up to two to three years to heal, but Dr. Nikolai Korpan, the physician who oversaw the Ukrainian politician's treatment, said Yushchenko is "fully capable of working."
Unlike earlier blood tests, the latest were sent to a laboratory in Amsterdam that uses a new analysis method that could test it for dioxin, Korpan said.
When first seen by the Austrian doctors Sept. 10, Yushchenko was in a critical stage but was "not on the verge of dying," Zimpfer said.
"If this dose had been higher, it may have caused death," he said.
Dioxin -- a contaminant found in Agent Orange -- is a byproduct of industrial processes such as waste incineration and chemical and pesticide manufacturing.
It is a normal contaminant in many foods, but a single high dose, usually in food, can trigger illness, London-based toxicologist John Henry said last month.
"We've never had a case like this -- a known case of large, severe dioxin poisoning," Henry said, leaving it unclear whether the dosage of dioxin administered to Yushchenko was meant only to make him ill or to kill him.
Tension in Ukraine's political crisis has abated with parliament's adoption of the electoral changes aimed at preventing fraud in return for handing over some presidential powers to the parliament.
Yushchenko wants to move his former Soviet republic closer to the West politically and is largely backed by the Ukrainian-speakers who want to end what they say has been mass corruption during the previous decade. The pro-Kremlin Yanukovych, who had the backing of outgoing President Leonid Kuchma and Russian leader Vladimir Putin, draws his strength from the Russian-speaking, industrial east, which accounts for one-sixth of Ukraine's population of 48 million.