Some protesters were seen stealing motorbikes which they set on fire along in the street. At times police struggled to maintain control as the fires continued to burn.
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Barack Obama has delighted the crowds at St Andrew's golf course as he teed off his visit to Scotland with a game of golf.
Britain's most senior counter-terrorism officer said "immense" progress had been made in the investigation into the Manchester bombing.
Scotland sees the best of today's weather but temperatures are a good 10C above average for the time of year across much of the UK.