Democrat Obama rolls to two big U.S. wins

WASHINGTON (Reuters) - Democrat Barack Obama easily won twomore nominating contests on Tuesday, extending his winningstreak over rival Hillary Clinton and building momentum in ahard-fought U.S. presidential race.

Obama rolled to decisive victories in Virginia and theDistrict of Columbia, running his hot streak to sevenconsecutive wins and expanding his lead in the pledgeddelegates who select the party's nominee.

Republican front-runner John McCain narrowly defeated hislast major challenger, former Arkansas Gov. Mike Huckabee, inVirginia, U.S. media projected, as McCain tried to move closerto clinching the party's nomination for the November election.

Maryland officials extended voting, which was supposed toend at 8 p.m. EST/0100 GMT on Wednesday, to 9:30 p.m. EST/0230GMT as rain and freezing temperatures created travel hazardsthroughout the region.

Obama, who would be the first black U.S. president, hadbeen favoured in all three of Tuesday's contests after his bigweekend wins in Maine, Louisiana, Nebraska, Washington and theVirgin Islands.

All three contests occurred in fertile territory for Obama,with large populations of the high-income and black voters whohave favoured the Illinois senator.

But exit polls in Virginia indicated Obama was cutting intosome of Clinton's core constituencies. He led among women andessentially split the votes of whites with Clinton, whilecrushing her 9-to-1 among blacks -- an even larger margin thanusual.

In Virginia, Obama was winning more than 60 percent of thevote with about half of the precincts reporting.

Obama had edged past Clinton in the race for pledgeddelegates who formally select a party nominee at a conventionin August. A total of 168 delegates were at stake in Tuesday'svoting.

Obama has 958 pledged delegates to Clinton's 904, accordingto a count by MSNBC -- well short of the 2,025 needed to clinchthe Democratic nomination.

(Additional reporting by Deborah Charles, Jeff Mason,Andrew Stern, Caren Bohan; Editing by Lori Santos)

(To read more about the U.S. political campaign, visitReuters "Tales from the Trail: 2008" online athttp://blogs.reuters.com/trail08/)