UTV's Marc Mallett says that tensions in Northern Belfast have been running high for weeks ahead of Monday's violence.
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The heavily pregnant Duchess of Cambridge refused to be put off by bitterly cold winds and snow as she greeted Irish Guards members.
Celebrations are taking place across Northern Ireland to mark St Patrick’s Day.
Police are investigating after an axe attack in Wolverhampton. A 22-year-old man has been arrested on suspicion of attempted murder.