U.S. presidential hopeful Barack Obama has an early lead in Saturday's nominating caucuses in the tiny U.S. territory of Guam.

With nearly one-quarter of the vote counted, Obama has won about 55 percent of the ballots in Guam, ahead of his rival Hillary Clinton. The caucuses are choosing delegates to the Democratic Party's national convention.

Even before ballot-counting finished, it was clear that more than twice as many Democrats voted in Guam caucuses this year than in 2004, the last U.S. presidential election year.

Guam, an island in the western Pacific, is nearly 13,000 kilometers from the U.S. capital in Washington. Its 175,000 residents cannot vote in the U.S. presidential election in November, but they have a small share of votes at the Democratic convention.

Clinton and Obama campaigned in the mainland U.S. Saturday, preparing for Tuesday's primary elections in North Carolina and Indiana, where a close vote is expected.

Guam will cast nine delegate votes out of a total of more than 4,000 (4,047) at the Democrats' convention in Denver in late August. Saturday's caucuses selected four delegates. The territory also has five so-called "superdelegates" - prominent officeholders or party officials who automatically have a vote at the party's meetings.

Meanwhile, voter surveys are showing that Obama's once-sizable lead in North Carolina has decreased. This week, he and Clinton have debated their conflicting views on whether the United States should temporarily suspend federal taxes on gasoline this year, to help American motorists hit by a sharp rise in energy costs.

Clinton and Senator John McCain, who will be the Republican Party's presidential nominee, both want to lift the gasoline tax, but Obama has charged this is an election-year gimmick that will result provide little if any savings for consumers.

Obama leads Clinton in the number of delegates pledged to support him for the party's nomination, but he trails her slightly in that tally of "superdelegates," who are not elected in state primaries or caucuses and are free to vote for either candidate.

Some information for this report was provided by AP and Reuters.