Speaking at a press conference as he prepared to leave the Vienna clinic today, Yushchenko made no direct comment about the doctor's findings or the Ukrainian investigation. He did not answer questions from journalists, but in prepared remarks, he praised opposition demonstrators in Ukraine who have been supporting him with street protests in recent weeks.
"The students declared a general national strike. We hadn't seen anything like that for the past 100 years. I think it would be appropriate to compare this to the fall of the Soviet Union or the fall of the Berlin Wall. I am very happy that we were able to mobilize the Ukrainian community to stand up for its rights," Yushchenko said.
Yushchenko also welcomed support from Ukrainian heavyweight boxer Vitali Klitschko -- who successfully defended his world championship title last night during a fight in Las Vegas, Nevada. "We were very pleased to see that when Vitali Klitschko fought last night, he was wearing orange," he said. "He fought wonderfully. And at the end, when he won, they raised a flag saying, 'Tak. Yushchenko!'"
Yushchenko's Austrian doctor, Michael Zimpfer, said there is no doubt that poisonous dioxin disfigured Yushchenko's face and continues to cause him other health problems. Zimpfer said he suspects the poisoning was deliberate, and possibly was administered through Yushchenko's food.
"It would be quite easy in fact to administer this amount in a soup that contains cream, because of the issue of fat solubility. As relates to the circumstances as regards a criminal investigation, this doesn't fall within our purview. We have made a final diagnosis as well as an additional diagnosis that we suspect a cause triggered by a third party. There is the suspicion of third-party [outside] involvement," Zimpfel said.
Ukrainian officials have denied allegations made by Yushchenko in the past that his political opponents in Kyiv are responsible for his poisoning.
In Washington, a U.S. State Department spokeswoman said the United States is "deeply concerned" by the finding of poisoning. Washington has urged the authorities in Ukraine to conduct a thorough investigation.
Yushchenko was returning from Austria to Ukraine today to continue his campaign for the 26 December rerun of the disputed presidential election runoff against Prime Minister Viktor Yanukovych.
For his part, Yanukovych has been pushing ahead with his own campaign in eastern Ukraine where most of his support is concentrated.
Backed by neighboring Russia, Yanukovych initially was declared the winner of a runoff on 21 November. But the Ukrainian Supreme Court later struck down those results on grounds of irregularities and ordered a new runoff on 26 December.
Correspondents report a modest crowd of about 5,000 people turned out at a rally in the eastern Ukrainian town of Luhansk yesterday to hear Yanukovych denounce the Supreme Court ruling. "The illegal but nevertheless pre-election period has begun," he said. "But we will go through it with dignity. The minimum we have to achieve is to confirm the results we achieved in the 21 November election round. Let's do it together and let's prove we are strong."
Ukraine's outgoing President Leonid Kuchma has promised an orderly ballot on 26 December and a peaceful transfer of power. Those comments were contained in a statement issued yesterday after Kuchma met with former U.S. diplomat Richard Holbrooke. Kuchma's statement also criticized a two-week blockade of his office by Yushchenko's supporters. [For more RFE/RL coverage and analysis of the political crisis in Ukraine, click here.]