The EU receives over 20 percent of its Russian gas imports through Belarus and the latest move in Moscow's arm-twisting of its neighbours renews European concern over its reliance on Rusiian energy supplies.

"We take these developments very seriously," EU spokesman Martin Selmayr said. "We call on both sides to resolve the dispute without delay and to create conditions for the timely resumption of deliveries," he told journalists in Brussels on Wednesday (1 August).

Gazprom doubled the price it charges Belarus for gas already in January, blaming rising international energy prices. The debt crisis erupted last week following the expiry of a six-month grace period, during which Belarus was allowed to delay paying the new $100 per thousand cubic metres price.

Earlier this year, Russia temporarily halted crude supplies to Minsk in a dispute over oil duties, which led to brief shortfalls in Poland and other European nations.

The dispute is similar Gazprom's demands in 2005 that Ukraine pay roughly twice its previous rate for natural gas a year.

When Ukrainian authorities refused, Gazprom reduced the pressure in the Ukrainian pipeline system in mid-winter. Ukrainian gas customers, including municipal utilities that heat homes, responded by drawing down fuel from volumes in the pipelines intended for export to Europe.