(Adds detail, background)
KIEV, March 21 (Reuters) - Ukrainian police detained the chief executive of state energy company Naftogaz on Friday in connection with a corruption investigation, Interior Minister Arsen Avakov said in an online post.
Naftogaz declined to comment on the report of Yevhen Bakulin's detention.
Naftogaz is responsible for the import and distribution of Russian natural gas in Ukraine. It also holds a monopoly on the shipment of gas from Russia's Gazprom via Ukraine to Europe.
Police are conducting three separate investigations into suspected corruption in the gas industry that may have cost the Ukrainian state about $4 billion, Avakov said on Facebook.
"The investigation is important not only for the sake of justice and the recovery of stolen assets. It is even more important as an inoculation against corruption in the new government," he said.
Bakulin, who was a close ally of former deputy prime minister Yuri Boiko, was appointed head of Naftogaz in 2010 under ousted president Viktor Yanukovich.
Earlier on Friday, international tensions over Ukraine ratcheted up another notch when President Vladimir Putin signed laws completing Russia's annexation of Crimea and the European Union followed the United States in imposing more sanctions against senior Russian officials. (Reporting by Pavel Polityuk; Writing by Alessandra Prentice; Editing by Gareth Jones)