Last year, Ukraine’s state-owned oil and gas company Naftogaz decided that it would not purchase any gas from the Russian giant Gazprom, due to escalating political tensions between the two countries.

However, due to a ‘take or pay’ clause in the supply contract between the two energy companies, which stipulates that Naftogaz must purchase a minimum level of gas from Gazprom, there may be repercussions for the Ukrainian firm.

“In 2015, Ukraine actually refused to buy Russian gas in the third quarter, and there was no agreement that the ‘take or pay’ rule is not applied in that period”, said Alexey Miller, CEO of Gazprom, in a statement to the Russian press.

“Taking this [minimum level] into account and the volume of gas delivered by Gazprom to Ukraine in the third quarter of 2015, Naftogaz Ukraine has been sent a bill for $2.549bn.”

On top of the $2.5bn gas bill, Russia is also demanding that Ukraine pay off a further $3bn for a loan

Gazprom has stipulated that it expects the outstanding bill to be settled within the next 10 days.

After pro-Russian President Viktor Yanukovych was ousted from his position in early 2014, the relationship between the two countries has turned sour.

Since then, Ukraine has attempted to wean itself off of its dependence on Russian gas and has bought minimal supplies from Gazprom as a result.

In retaliation, on top of the $2.5bn gas bill, Russia is also demanding that Ukraine pay off a further $3bn for a loan that was given to Yanukovych when he held office. However, the new government refuses to recognise it and has said that it has no intention of repaying it in full.

Ukraine’s government has asked that Russia grant it a 20-percent reduction in its debt repayments, but Moscow turned down the request and has said that it will take the country to court if it is not paid the money it is owed.

For more on this story, stay tuned for an extended report in the next issue of European CEO