* Ruzhechko accused of polluting oil network
* His lawyer says Russia has presented no proof
* Lithuania has history of refusing Russian extradition requests
* Oil buyers seeking compensation for tainted oil (Updates with detail, background)
By Andrius Sytas
VILNIUS, July 19 (Reuters) - Roman Ruzhechko, a suspect in a Russian probe into a major oil pipeline contamination earlier this year, has asked for political asylum in Lithuania, a Vilnius district court spokesman told Reuters on Friday.
Russian prosecutors have charged Ruzhechko, an executive at a small oil transport firm, and several other people in a criminal conspiracy to pollute the network, which is owned and operated by the country's oil pipeline monopoly Transneft.
A lawyer for Ruzhechko has said there was nothing in the prosecutors' files that proved his client's guilt.
The contamination was discovered in April and led to a major disruption of supplies from Russia, the world's second largest oil exporter. Buyers are now seeking compensation worth tens of millions of dollars.
The contamination involved high levels of organic chloride found in oil sent via the Druzhba ("Friendship") pipeline and to the Baltic port of Ust-Luga.
Druzhba can pump one million barrels per day or the equivalent of one percent of global oil demand and serves refiners in Germany, Poland, the Czech Republic, Slovakia, Hungary, Ukraine and Belarus.
Russian President Vladimir Putin told the boss of Transneft, Nikolai Tokarev, that the contamination was a serious blow to Russia's image as a reliable energy supplier.
Lithuania's prosecutor general office said Ruzhechko was detained in Lithuania on an Interpol warrant for 48 hours.
At a hearing on Thursday, the Vilnius district court authorised a three-month detention of Ruzhechko at the request of prosecutors, the court spokesman said.
A country has 40 days to present a request to extradite a person, Lithuania's prosecutors spokesman said.
In 2006, Lithuania refused to extradite former YUKOS employee Igor Babenko to Russia on the grounds that he had been granted political asylum during the extradition process, Lithuanian media reported.
Russian prosecutors accused several YUKOS executives of tax evasion and embezzlement. YUKOS founder Mikhail Khodorkovsky denied the charges which he said were a product of the Kremlin's revenge for his political ambitions.
Ruzhechko is general director of a company called Samartransneft-Terminal, which used to own another oil transport firm, Nefteperevalka.
Russian prosecutors have detained two executives from Nefteperevalka, two other suspects and have issued arrest warrants for Ruzhechko and the former owner of Nefteperevalka, Roman Trushev.
Prosecutors alleged Trushev and Ruzhechko directed the conspiracy but did not say on what basis they made that conclusion.
Documents seen by Reuters this week certified that Transneft gave a clean bill of health to oil deliveries from Nefteperevalka. (Reporting by Andruis Sytas; writing by Dmitry Zhdannikov; editing by Jan Harvey and Jason Neely)
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