An explosion ripped through a natural gas pipeline in central Ukraine on Tuesday in what the country's interior minister said might have been an act of sabotage.
Officials at Russian energy giant Gazprom said the blast along the Urengoy-Pomary-Uzhgorod pipeline near Poltava hadn't disrupted its gas deliveries to Europe because they are flowing through alternate routes. Poltava is about 120 miles east of Kiev and about the same distance west of the areas of Ukraine where fighting has taken 300 lives in recent weeks.
Gazprom on Monday cut off gas supplies to Ukraine following a monthslong dispute over pricing and Kiev's overdue bills for past deliveries. After Ukraine failed to make a $1.95-billion payment, Gazprom said Ukrainian purchases must now be paid in advance before delivery.
The ongoing dispute over gas sales between the two former Soviet republics and bitter fighting between Ukrainian government troops and pro-Russia separatists raised fears that the blast might have been deliberate.
"Several theories of what happened are being considered, including the main theory of a terrorist act," Interior Minister Arsen Avakov said in a statement.
Ukrainian authorities refer to the gunmen who have seized much of eastern Ukraine's Donetsk and Luhansk regions as terrorists.
European Union officials had been mediating negotiations between Russia and Ukraine over gas deliveries until Monday, when a deadline for nearly half of what Moscow says it is owed by Kiev expired without agreement or payment.
Gazprom, in which the Russian government is the major shareholder, boosted the price of natural gas for Ukraine by more than 80% in April in a move seen as Kremlin retaliation for the ouster of Ukraine's former pro-Russia president, Viktor Yanukovich. The Russian government also canceled a discount it had offered Kiev as part of its leasing arrangement for the Black Sea Fleet base in Crimea after Russian troops seized the Ukrainian peninsula and Russian President Vladimir Putin annexed it to Russia in March.
The armed clashes in eastern Ukraine were sparked by pro-Russia separatists after the Crimean annexation -- a move by the Kremlin to secure its naval base as Kiev's new leaders looked to realign their diplomacy and economy toward the European Union.
Ukraine had been paying $268.50 per thousand cubic meters of gas from Russia when Yanukovich was in power. With the favorable terms revoked after his ouster, Gazprom raised the price to $485 per thousand cubic meters and recalculated Kiev's arrears to reflect the higher price. Gazprom announced Monday that it plans to sue Ukraine's Naftogaz energy agency in international court to recover the $4.5 billion it says it is owed.