BY NANCY SAN MARTIN

More than 80 percent of Puerto Rico's 2.4 million voters swamped precincts across the island to cast their ballots in a divisive gubernatorial race that was too close to call Tuesday night.

Preliminary results gave a slight lead to former governor Pedro Rosselló, 60, of the New Progressive Party over Aníbal Acevedo Avilá, 42, of Popular Democratic Party.

But with the counts of paper ballots slowly trickling in, election officials said they did not expect a definitive tally until sometime today.

LEAD SHRANK

Polls had consistently showed Rosselló as the front-runner with as much as a 10 percentage point lead, but the gap narrowed in recent days.

Heightening the interest of many voters in the U.S. territory was the thorny issue of whether they should back Rosselló's push to turn Puerto Rico into the 51st U.S. state or support the current commonwealth status as favored by Acevedo, the island's nonvoting representative in Washington.

Ruben Berrios of the Puerto Rican Independence Party was running a distant third in his fifth run for the governorship. Outgoing Gov. Sila Calderón, also of the Popular Democratic Party, did not seek reelection.

Rosselló, elected twice to four-year terms, left office in 2000 amid a corruption scandal in which officials from his administration were accused of diverting $2.2 million from the defunct San Juan AIDS Institute. The case, which included various arrests and convictions, tainted Rosselló's reputation, even though he was never charged with any crime.

During the campaign, Rosselló acknowledged there were problems during his previous tenure but pledged to create a task force that would detect potential corruption to ensure a clean government.

Acevedo has focused on the corruption scandal and vowed to lead a clean government.

Both candidates also have promised to give Puerto Rico a third shot at defining its relationship with the United States, despite votes in 1993 and 1998 in which commonwealth status won narrowly.

The topic has become particularly divisive this year because of controversy over U.S. military bombing exercises on the island of Vieques and the closure in March of the Roosevelt Roads Naval Base in Ceiba.

THE VIEQUES FACTOR

''The Vieques issue had many statehood people concerned that there was a perception of distancing from the United States,'' said Félix Matos-Rodríguez, director of the Center for Puerto Rican Studies at Hunter College in New York.

The candidates also have pledged to tackle other problems affecting the island, including increased crime, high unemployment, a struggling education system and the waning economy.

The Caribbean island has been a U.S. territory since 1898 and was given limited autonomy in 1952. Puerto Rico's four million residents have U.S. citizenship but pay no federal taxes. They can serve in the military but cannot vote in the U.S. presidential election.