Ukraine's former national security chief said Thursday that President Viktor Yushchenko's dioxin poisoning still needs to be proven.

"We have papers from abroad, but we need a Ukrainian examination," said Oleksandr Turchinov at a news conference here.

Turchinov said Yushchenko has so far not fulfilled his pledge to undergo tests in Ukraine, despite the fact that only Ukrainian examination results are admissible in court.

The papers presented by foreign medical institutes were not adequate to substantiate the fact of poisoning, Turchinov said.

Turchinov said he did his best at the post of national security chief to investigate the poisoning, but Yushchenko refused to undergo tests in Ukraine.

The legal proceedings over the case cannot be launched because there is no legal medical test conclusion to confirm the poisoning, Turchinov noted.

Yushchenko fell ill last September during the hotly contested presidential election, and was later diagnosed as having suffered massive dioxin poisoning. Foreign medical experts said the dioxin content in Yushchenko's blood is 6,000 times the normal level.

The poisoning knocked him off the campaign trail for several weeks.

Turchinov resigned as head of the State Security Service after Yushchenko dismissed the government of Turchinov's ally, Prime Minister Yulia Tymoshenko, on Sept. 8.

Source: Xinhua