SAN JUAN, Puerto Rico (AP) _ Two prominent surrogates of Barack Obama and Hillary Rodham Clinton stumped for the candidates Wednesday in this U.S. island territory, which has 55 delegates at stake in its June 1 Democratic primary.

Michelle Obama toured the Puerto Rican capital of San Juan on behalf of her husband, who remains locked in a marathon fight for the Democratic presidential nomination. Her first visit to the island coincided with Chelsea Clinton's second trip to Puerto Rico to pitch her mother's candidacy.

At a stop in San Juan's colonial district, Obama greeted the islandwide steering committee for her husband's campaign. She said he believes that only Puerto Ricans should decide on whether the island will continue its commonwealth status, become a U.S. state or opt for independence.

"That's an issue that should be decided by the voters here. Self-determination is a critical part of democracy," Obama told a local TV reporter.

Much of Puerto Rican politics revolve around the island's relationship to Washington, with islanders about evenly divided on the issue.

Meanwhile, the U.S. Navy denied Chelsea Clinton permission to campaign on a former bombing range on the outlying island of Vieques. The range was closed in April 2003 after years of protests over two errant bombs that killed a security guard.

Hillary Clinton's campaign wanted to use the site as a setting to discuss her plan to clean the land up and hand over some parcels to local residents. But Navy spokeswoman Lt. Lara Bollinger said no one is allowed to campaign on federal property.

Instead, the 28-year-old former first daughter held an event nearby and spoke with residents about her mother's concerns and plans for Vieques and the island of Culebra, campaign spokesman Philippe Reines said.

Hillary Clinton has run much stronger among Hispanics throughout the campaign, but Obama is contesting the Spanish-speaking commonwealth, which holds one of the last primaries.

Obama currently has a total of 1,887 delegates, leaving him just 139 delegates short of the 2,026 needed to clinch the nomination. Clinton has 1,718 delegates, according to the latest tally by The Associated Press.

The Illinois senator suffered an embarrassment here earlier this year when his most prominent Puerto Rican supporter, Gov. Anibal Acevedo Vila, was charged with conspiring to violate federal campaign laws, defraud the Internal Revenue Service and give false testimony to the FBI.

As one of seven superdelegates from the island, Acevedo will cast one of Puerto Rico's 63 votes at the Democratic convention. The total includes one delegate who will be named later.

Puerto Ricans are U.S. citizens but cannot vote in general presidential elections while on the island. Their representation in Congress is restricted to a single nonvoting member.