Voters in Virginia, Maryland and Washington DC have gone to the polls to choose Democratic and Republican candidates to represent them in November's presidential election.

Senator Barack Obama won all three Democratic primaries, with convincing margins of victory.

Hillary Clinton heard the election results in Texas, where she is hoping to regain the initiative in the race, when the state holds its primary on 4 March.

Senator John McCain also won a clean sweep, with victories in all three of the Republican contests.

Mike Huckabee - Mr McCain's main rival - put up a competitive race in Virginia, but was comprehensively beaten in Maryland and Washington DC.

Turnout was high throughout the region, despite the wintry weather, with polling stations reporting long queues.