Ukraine's security service has denied any involvement in the poisoning of opposition presidential candidate Viktor Yushchenko.
In a statement Thursday, the State Security Service said it had nothing to do with what it called Mr. Yushchenko's worsening health.
The pro-Western opposition leader fell ill in September during a heated presidential campaign and his face became disfigured. Doctors say he was poisoned with dioxin.
Mr. Yushchenko told the Associated Press last week that he was probably poisoned at a September dinner with Ukrainian security agents.
Mr. Yushchenko faces pro-Russian Prime Minister Viktor Yanukovych Sunday in a court-ordered re-vote to replace last month's fraudulent balloting.
Russian President Vladimir Putin told reporters today he is willing to work with whoever wins.
Some information for this report provided by AFP and Reuters.