Head of Gazprom Alexei Miller said Ukraine threatened to tap Russian gas bound for Europe.
Gazprom spokesman says the company will not deliver any gas to Ukraine unless it receives a pre-payment.
Ukraine and Russia head for international arbitration court after gas price talks fail.
Ukraine and Russia fail to reach a deal in gas price dispute with Gazprom threatening to cut supplies.
Russia call for Andriy Deshchytsia to be fired after he tells anti-Moscow protesters Russian President is a dickhead.
Ukraine president declares Sunday a national day of mourning for 49 servicemen who died in Luhansk plane attack.
Moscow rebukes Ukrainian police for 'inaction' after rioters attack the Russian embassy in Kiev.
It remains unknown who is responsible for the device planted near office of billionaire chocolate tycoon.
Ukrainian interior minister says three tanks have crossed border from Russia as fighting resumes.
Vladimir Putin suggests Russia has made its final offer with $100 reduction.
Kiev's senior adviser says Ukraine is planning to shut down Russia border immediately.
US economy forecast to grow 2.1% in 2014 while China to grow 7.6%.
Best photos of the day: 10 June 2014
Putin holds talks with Obama and Ukraine president-elect Poroshenko in effort to solve Ukraine crisis.
US president warns Russia president Putin over funding and encouraging insurgency in eastern Ukraine
Russian president says former US Secretary of State 'has never been too graceful in her statements.'
Leaders of G7 nations warn Russia of fresh sanctions if Moscow does not help resolve Ukraine crisis
Naftogaz to split into three companies in line with European Union norms.
Kiev claims 300 rebels killed and 500 wounded in "anti-terrorist operation" in eastern city.
Poland's foreign ministry Radoslaw Sikorski says Moscow will use the two helicopter carriers to threaten its neighbours
US President says security of European allies is "sacrosanct" on visit to Poland.
Best photos of the day: 3 June 2014.