The Ukrainian government has confirmed that two Western energy companies have been awarded the right to develop two large shale gas fields.
The anglo-Dutch company Shell, and Chevron from the United States, have beaten off competition from three other rival bids – including one from Russia.
One area, Olesska, is in the western region of Lviv – while Yusivska, is in the eastern Donetsk and Kharkiv regions.
Although relations with Moscow have improved under President Yanukovitch, Ukraine has been trying to reduce its dependence on gas imports from Russia.
Ukraine’s prime minister Mykola Azaraov said the decision was approved at a meeting of government ministers on Thursday, adding that the two gas deposits had enormous capacity.
Ukraine has Europe’s third-largest shale gas reserves after France and Norway, according to the US state Energy Information Administration.
The technique used to exploit the fields will be the process known as fracking – or hydraulic fracturing – which has proved controversial elsewhere. Environmentalists say it may contaminate groundwater and trigger earth tremors.