Russian gas giant Gazprom said on Tuesday it had charged Ukrainian energy firm Naftogaz with a $5.3 billion bill for gas it did not buy under a take-or-pay clause.

Gazprom said the bill related to supplies in the second to fourth quarters of last year and that Ukraine had to pay the bill within 10 days.

Ukraine has not bought Russian gas since November 2015.

Take-or-pay requirements make consumers pay for gas whether they take physical delivery or not.

Source: Reuters