KIEV, Apr. 26 - Ukraine’s national energy company Naftogaz Ukrayiny will have to pay more than $1 billion to Russian gas giant Gazprom before May 7 for gas imported in April, a Naftogaz official said Tuesday.

Ukraine is buying Russian gas at about $296 per 1,000 cu m in the second quarter of 2011, compared with $264/1,000 cu m in the first quarter.

Naftogaz needs to make monthly payments to Gazprom within the first week of each next month to comply with a 10-year natural gas agreement both signed in January 2009.

A failure to pay on time for gas imports may provoke Gazprom to suspend gas supplies to Ukraine that may in turn affect other countries in Europe.