KIEV, Dec. 21 ??“ Separmurat Niyazov, the authoritarian president of Turkmenistan, the Central Asian country that supplies most of Ukraine??™s natural gas needs, died early on Thursday of a heart attack, state controlled media reported.

Niyazov, 66, who made himself president-for-life in 1999, has been strictly controlling exports of gas from Turkmenistan, which is thought to have the world??™s fifth largest gas reserves.

But he prepared no official successor suggesting that rival clans may rush for control of the foreign policy and the lucrative gas sector that may potentially lead to gas supply problems.

"If Niyazov??™s death results in political instability and social unrest, this may lead to the gas supply from Turkmenistan to RosUkrEnergo [Russian-Ukraine energy joint venture] and Ukraine being disrupted," said a research note from Deutsche UFG Bank in Moscow.

???If that happens, Ukraine will have to seek other sources and Russian deliveries will be a natural choice. At the same time, Gazprom will be unable to provide 41 billion cubic meters of gas on short notice.???

President Viktor Yushchenko met Prime Minister Viktor Yanukovych on Thursday to discuss among other things the death of Niyazov. They also discussed any potential impact on Ukraine, which depends on Turkmen gas supplies.

Yushchenko will fly to Ashgabat for the funeral ceremony that has been scheduled on Dec. 24.

Gurbanguly Berdymukhammedov, deputy prime minister, who was declared the acting president until the next election, assured international community that Turkmenistan will keep its foreign policy unchanged.

???Turkmenistan will continue the policy of Separmurat Turkmenbashi [the Ruler of all Turkmens],??? Berdymukhammedov said on state television. ???The Turkmen people will always be loyal to precept, instructions and lessons of its Chief and will complete his all proceedings.???

Turkmenistan will stick to the policy of neutrality and will honor its all international contracts and obligations, Berdymukhammedov said.

RosUkrEnergo, a gas trader controlled by Russian state gas giant Gazprom and the only gas supplier to Ukraine, has been purchasing most of its gas from Turkmenistan.

RosUkrEnergo is to deliver about 56 billion cubic meters of gas to Ukraine in 2007, or 74% of the country??™s overall natural gas needs, suggesting that any supply disruptions may trigger major shortages.

???Of course, this matter is of a big concern to us,??? Yanukovych said. ???But we hope that the worst thing that could happen has already happened: a good friend of Ukraine, Separmurat Niyazov, has died.???

Russia reacted to the death by saying it hoped Turkmenistan would stick to Niyazov??™s course. "We count on the new Turkmenistan leaders continuing their course and further developing bilateral ties," said Sergei Prikhodko, a Kremlin aide.

Although Niyazov??™s heart trouble was long known, details of the leader??™s health ??“ as with everything else related to state matters ??“ had been kept highly secret. (tl/ez)