The United States has warned Russia that it would be a "grave mistake" to embark on military intervention in Ukraine.
"I don't think there should be any doubt whatsoever that any kind of military intervention that would violate the sovereign territorial integrity of Ukraine would be a huge - a grave mistake," US Secretary of State John Kerry said.
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The singer ended speculation over who would perform by saying "the rumors are true" to her 63 million Twitter followers on Friday morning.
There will be lighter winds for all of us than yesterday, although it will still feel cool.
Senior fashion analyst at Mintel Tamara Sender said: "For the first time ever sales of trainers have overtaken high heels."