Amateur footage appears to show a number of police cars chasing a vehicle along a road near the US Capitol building.
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Labour have lost the Copeland by-election, a seat they had held since 1983, as the Conservatives edged the vote by 2,000 votes.
Labour have held onto the crucial seat of Stoke-on-Trent, brushing aside UKIP leader Paul Nuttall in the process.
A highly toxic chemical was used in the death of North Korean leader Kim Jong-un's half brother last week, tests have shown.