Russia turned off the gas taps to Ukraine this morning after its deadline for an unpaid gas bill passed.

Russian state energy firm Gazprom extended the original deadline by a week after Ukraine seemed to be playing ball with its bigger neighbour.

The firm said it switched Ukrainian energy firm Naftogaz to a pre-payment system because of the “chronic non-payment of its gas bills”.

Russia is demanding $4.5 billion (£2.7bn), with $1.5 billion (£0.9bn) of that is for gas used in November to December 2013. The remaining $3 billion (£1.8bn) is for April to May 2014 when Russian scrapped a discount.

Ukraine’s Prime Minister Arseniy Yatseniuk today suggested the price was not acceptable, reportedly telling energy officials: “We won’t subsidise Russia.”

He countered the cut-off, by asking his energy ministry to draw up laws attracting EU and US investors to improve its gas network, reported news agency Interfax-Ukraine.