Amateur footage appears to show a number of police cars chasing a vehicle along a road near the US Capitol building.
ITV News cannot independently verify this video.
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The victim, a man in his 40s, is being treated in hospital for "life-changing" injuries after the attack by two men who remain on the run.
Heavy security presence as 64,000 fans gather at the Stade de France stadium for the Six Nations rugby match between France and Italy.
Today's rain will clear into the North Sea tonight, but winds will stay strong, with showers feeding in to the north and west.