More than 500,000 tweets have been sent using the hashtag #twitterisblockedinTurkey since the service was banned in the country last night, according to social media search engine Topsy.
Analysis also shows 100,000 have used the hashtag #turkeyblockedTwitter at the time of writing.
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In an embarrassing setback for the president, Republicans failed to reach the number of votes to pass his new healthcare act into law.
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Some of Britain's biggest stars of the stage and screen will be honoured at Buckingham Palace later today.