Barack Obama to make rare visit to Puerto Rico

US President Barack Obama is to make a rare visit to Puerto Rico, marking the first official trip to the island by a sitting US president since 1961.

The visit is being seen by some as an indirect bid for the votes of Puerto Ricans in the swing-state of Florida during next year's presidential poll.

The 3.8 million residents of the US Caribbean territory are US citizens but cannot vote for the president.

During his stay, Mr Obama will attend a Democratic National Committee event.

The president visited the island in 2008 during his campaign for the Democratic nomination, promising to return if elected president.

The BBC's Julian Miglierini in San Juan says many people there believe the visit is aimed at courting mainland America's Puerto Rican electorate - and Hispanic voters in general - as they could hold the key to Mr Obama's re-election in 2012.

The president has called for broad reform of the US immigration system, an issue affecting many Hispanics with ties to the 11 million US illegal immigrants.

Mr Obama is scheduled to meet Puerto Rico's governor on Tuesday to discuss the political status of the territory.

Analysts have said Mr Obama's trip to the Puerto Rican capital of San Juan, which is only expected to last about five hours, will also focus on the impact the economic crisis has had on the territory.

Meanwhile, roughly 20 pro-independence demonstrators held an all-night vigil in San Juan ahead of the president's visit, calling for the release of three Puerto Rican nationalists imprisoned in the US.