With 15 out of 21 districts reporting, Obama was ahead with 1,393 votes to 1,222 for those pledged to Hillary Rodham Clinton.

More than 3,000 votes were expected in heavy turnout at caucuses in the U.S. territory, where neither candidate campaigned.

Four pledged delegate votes were at stake on the island 8,000 miles from Washington. Guam also has five superdelegates and some of those are being determined in the caucus voting as well.

Slow ballot-by-ballot counting was under way in the territorial legislative building after votes were hand carried from some 20 caucus sites.

Long lines of voters were reported in schools, community centers and other caucus sites that were open for voting all day Saturday.

U.S. citizens in Guam have no vote in the November presidential election, but the close Clinton-Obama race is giving them an unaccustomed role in the nomination process.

Voters picked eight pledged delegates who will have only one-half vote each at the Democratic National Convention in Denver in August.

Presidential caucuses on Guam usually pass without much notice from the candidates.

This time, Obama and Clinton made their case for the territory's four regular delegates with local advertising and long-distance interviews.

Lines formed early at some caucus sites.

Cynthia Estrada of Dedeo said she was making up her mind while waiting to vote, but she was leaning toward Clinton.

"She's had the experience," she said. "She's got her husband to help her."

Yona resident Tommy Shimizu said he was voting for Obama delegates.

"It's the fact that he grew up in Hawaii, and I think he can make change," he said. "I think it's time for that."

Clinton and Obama pitched improved health care and economic opportunity as they courted Guam voters from across the international date line.

Both candidates bought local advertising and conducted media interviews. In their protracted race for the nomination, no contest is being ignored.

Both Clinton and Obama say they've got the better health plan for Guamanians.

Obama said in an interview with Pacific Daily News that he would support reexamination of a $5.4 million Medicaid spending limit imposed on the territory. Clinton's husband, former President Bill Clinton, told KUAM radio earlier that his wife would work to remove the cap.

Hillary Clinton also has called for Guamanians to be able to vote in presidential elections.