KEY POINTS:
WASHINGTON - John McCain clinched the Republican presidential nomination today and Democrat Hillary Clinton won crucial showdowns with rival Barack Obama in Ohio and Texas to breathe new life into her struggling campaign and prolong the Democratic race.
The wins for Clinton, a New York senator, gives new life to her campaign and is likely to send the hotly contested Democratic race on toward the next major contest - Pennsylvania on April 22.
Obama scored an easy win in Vermont and Clinton won Rhode Island. Clinton's Ohio and Rhode Island victories broke Obama's string of 12 straight wins in their hard-fought duel to be the Democrat who squares off against McCain.
Clinton was under pressure to win in the two biggest states, Ohio and Texas.
Turnout was heavy in all four states, and the Democratic campaigns of Obama, an Illinois senator, and Clinton traded accusations of irregularities at the polls in both Ohio and Texas.
An Ohio judge granted a request from the Obama campaign to extend voting in some Cleveland-area precincts.
Clinton and Obama were deadlocked at 49 per cent with more than one-quarter of precincts counted in Texas. But Clinton was later projected as the winner.
McCain's four big victories in Vermont, Ohio, Texas and Rhode Island drove his last major rival, former Arkansas Governor Mike Huckabee, out of the race and gave McCain more than the 1,191 delegates needed to win the nomination.
President George W Bush will greet the Arizona senator at the White House on Wednesday and back his campaign.
"I am very pleased to note that tonight, my friends, we have won enough delegates to claim with confidence, humility and a sense of great responsibility that I will be the Republican nominee for president of the United States," he told supporters in Dallas.
"The contest begins tonight," the former Navy fighter pilot and prisoner of war in Vietnam said, looking ahead to a match-up with either Obama or Clinton in the November presidential election.
- REUTERS