Democrat Barack Obama easily won two more nominating contests on Tuesday, extending his winning streak over rival Hillary Clinton and building momentum in a hard-fought U.S. presidential race.
Obama rolled to decisive victories in Virginia and the District of Columbia, running his hot streak to seven consecutive wins and expanding his lead in the pledged delegates who select the party's nominee.
Republican front-runner John McCain narrowly defeated his last major challenger, former Arkansas Gov. Mike Huckabee, in Virginia, U.S. media projected, as McCain tried to move closer to clinching the party's nomination for the November election.
Maryland officials extended voting, which was supposed to end at 8 p.m. EST/0100 GMT on Wednesday, to 9:30 p.m. EST/0230 GMT as rain and freezing temperatures created travel hazards throughout the region.
Obama, who would be the first black U.S. president, had been favored in all three of Tuesday's contests after his big weekend wins in Maine, Louisiana, Nebraska, Washington and the Virgin Islands.
Obama had edged past Clinton in the race for pledged delegates who formally select a party nominee at a convention in August. A total of 168 delegates were at stake in Tuesday's voting.
Obama has 958 pledged delegates to Clinton's 904, according to a count by MSNBC -- well short of the 2,025 needed to clinch the Democratic nomination.