KIEV, April 28 (RAPSI) – Ukrainian government has decided file a lawsuit against Russian gas giant Gazprom, acting Ukrainian Prime Minister Arseniy Yatsenyuk told journalists Monday.

“The Ukrainian Government and Naftogaz Ukraine have decided to file a lawsuit against Russia’s Gazprom,” Yatsenyuk said. “We sent a pretrial notice to the Russian monopoly today. Under the contract, it must provide a clear answer to several questions, including the price of gas, within 30 days.”

Ukraine’s suit will also require that several contractual provisions be reviewed, according to Yatsenyuk.

Ukrainian Prime Minister said they expect Gazprom to respond to the notice and hope for an out-of-court settlement. “We hope that the Russian monopoly will avoid litigation by accepting the terms advanced by the Ukrainian government and Naftogaz,” Yatsenyuk said.

After Crimea region held a referendum and voted to secede from Ukraine and join Russia, Ukraine refused to pay the new gas prices being demanded by Gazprom, calling them an “economic assault” and “political prices.”

Gazprom almost doubled the natural gas price for Ukraine, demanded immediate payment of $.2.2 billion worth of outstanding gas bills this month, and then sent an extra $11.4 billion gas bill to Ukraine’s Naftogaz, citing the “take or pay” contractual stipulation under which consumers must pay for gas regardless of whether they take physical delivery.

Europe relies on Russia for a third of its gas needs, and 40% of that gas is shipped via Ukraine.