Officials from Ukraine, Russia, and the European Union will hold talks in Brussels on June 9 in an effort to resolve Kyiv's natural-gas debt to Moscow.

A Russian Energy Ministry official said the three sides will also negotiate a price for Ukraine's gas imports from Russia.

Ukraine wants to change the conditions of a 2009 contract that locked Kiev into buying a set volume of gas, whether it needs it or not, at $485 per 1,000 cubic meters - the highest price paid by any client in Europe.

Kyiv insists on a price of $268.50 per 1,000 cubic meters while Russia stands by its demand for $485.

Ukrainian Prime Minister Arseniy Yatsenyuk has threatened to take the issue to an international arbitration court in Stockholm if Moscow does not agree to the lower price.