BY NANCY SAN MARTIN

Voters in Puerto Rico apparently chose their Washington representative as the island's new governor over a pro-statehood candidate. But the results were so close that a recount is mandatory, election officials said Wednesday.

The State Elections Commission certified that Aníbal Acevedo Vilá of the ruling Popular Democratic Party, which favors continuing the U.S. territory's commonwealth status, narrowly defeated former Gov. Pedro Rosselló of the pro-statehood New Progressive Party.

However, Acevedo's party appeared to have lost control of the island's bicameral legislature to the New Progressives and voters narrowly chose Rosselló's running mate as Puerto Rico's new nonvoting delegate to the U.S. Congress.

The power-sharing is a first for the island.

''The people have given the mandate to me, but also to the [New Progressives],'' Acevedo told a news conference in San Juan. ``The people said with their vote that they want a shared government.''

Puerto Rico law mandates recounts when the spread is less than 0.5 percent of the total vote. Acevedo, according to official results, appeared to have won by just 4,000 votes in a race that drew more than 80 percent of the island's 2.4 million voters. With 98 percent of the votes counted, Acevedo had 48.38 percent and Rosselló had 48.18.

Ruben Berrios of the Puerto Rican Independence Party came in a distant third with just 2.7 percent of the vote. Under Puerto Rican election laws, the low result meant the party lost its legal recognition. Party leaders said they would organize a signature drive to win back the recognition.

Analysts said the results indicated many Puerto Ricans' dislike for Rosselló, who left office amid allegations of corruption, and a rejection of his push for statehood through yet another referendum on the contentious issue.

Acevedo touted a constitutional convention as a way to clarify Puerto Rico's status, a pledge that earned him the support of a significant number of independence backers.

''[Acevedo] won on the basis of a need for a constitutional convention,'' said Javier Colón, head of the political science department at the University of Puerto Rico. ``Voters were turned off by Rosselló's yes or no vote on a referendum.''

Two previous attempts to win support for statehood were narrowly defeated in nonbinding referendums held during Rosselló's two previous terms as governor, from 1993 through 2000.

Officials said the recount would begin Monday but did not expect a drastic change in the results. ''The numbers could still vary, but not by much,'' Elections Commission President Aurelio Gracia told reporters in San Juan.