The chief executive of Russian gas exporter Gazprom accused Kiev of adopting an "unconstructive" position in gas talks and of using blackmail to try to get an "ultra-low" price.
Speaking to Russia's Prime Minister Dmitry Medvedev in a meeting open to reporters, Gazprom's CEO Alexei Miller said the debt Gazprom was asking for was "less than that which was required for the time period."
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Accompanied by the Duke of Edinburgh, the Queen will attend the opening ceremony of the fifth session in the Holyrood chamber.
Ms Leadsom has received the backing of Ian Duncan Smith, the former work and pensions secretary.
The former shadow work and pensions secretary is considered a more viable candidate than Angela Eagle, a Labour source has told ITV News.