The United States on Monday urged the Ukrainian government to fully investigate the "terrible" poisoning of opposition leader Viktor Yushchenko with the highly toxic substance dioxin.  

"It was terrible news to hear, and it's certainly disturbing reports," White House spokesman Scott McClellan said when he was asked at a news briefing about the US reaction to the poisoning of Ukrainian presidential candidate Yushchenko.

"I know the Ukraine government is investigating this matter fully, as they should," McClellan said.

Yushchenko was the victim of poisoning by dioxin, his doctor, Michael Zimpfer, said Saturday. "There were high concentrations of dioxin, most likely orally administered," said Zimpfer, director of the Vienna Rudolfinerhaus Hospital, where Yushchenko has been receiving treatment."

Dioxin is a by-product of industrial processes such as was teincineration and chemical and pesticide manufacturing. Yushchenko repeatedly claimed that he was poisoned by his political rivals.

In response to reports the US is intervening Ukraine's election and funding the opposition, McClellan claimed that "We do not and have not supported any particular candidate in Ukraine's presidential election."

"Our assistance is to support free and fair elections that reflect the will of the people, and that's what we do all over the world," the spokesman said.

Ukraine has been in a political crisis since the Nov. 21 presidential election, victory in which has been claimed by both pro-Moscow candidate, Prime Minister Viktor Yanukovich, and pro-Western candidate, opposition leader Viktor Yushchenko. Ukraine's Supreme Court has ordered to have a new runoff vote on Dec. 26.

(Xinhua News Agency December 14, 2004)