Secretary of state John Kerry has said that the US is not looking for confrontation with Russia over the Ukraine.
Kerry urged Russian President Vladimir Putin to be "very careful" in his judgments over the situation in Ukraine and that the two nations need not get into a "Cold War" stand-off over the country.
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One person has been confirmed dead and several are injured in the ongoing incident in Las Ramblas.
A number of fatalities and several injuries have been reported after a van has crashed into people in the Ramblas area of Barcelona.
John Underhill said geological changes 55 million years ago mean the UK's geology is unsuitable for shale oil and gas production.