U.S. President Barack Obama has reiterated his support for a referendum to allow Puerto Ricans to decide whether to remain a part of the United States.

On a rare presidential visit to the semi-autonomous U.S. Commonwealth Tuesday, Mr. Obama pledged to “stand by” the people of Puerto Rico, as soon as they make a “clear decision.”

The president supports a vote before the end of next year that would allow the island's residents to choose between statehood, independence or remaining semi-autonomous.

His brief stop in Puerto Rico, paying the island its first official presidential visit in 50 years, is seen as a smart move in courting the increasingly powerful Hispanic voting bloc for his 2012 re-election bid.

After landing in San Juan Tuesday, President Obama told an enthusiastic crowd that the aspirations and struggles of Puerto Ricans mirror those across the United States. He highlighted efforts to address the challenges facing the island, including education, health care and the economy.

Puerto Rico received $7 billion in economic stimulus money, but is struggling with a 16 percent unemployment rate, far above the national level. The island's governor, Luis Fortuno, says the stimulus has led to net gains in employment, although it has taken a long time for the spending to have an effect.

During his five-hour stop, Mr. Obama met with Fortuno at the governor's mansion, and was to attend a Democratic National Committee event in the territory.

The visit fulfills a promise Mr. Obama made during a campaign stop on the island in 2008 that he would return if elected president.

Puerto Ricans are U.S. citizens, but the island does not vote in U.S. general elections. Puerto Ricans, however, are still an important part of the voting public, as those living within the 50 states make up the second-largest group of Hispanics in the U.S. after Mexicans.

Mr. Obama is the fifth U.S. president to travel to the island and the first since then-president John F. Kennedy went there in 1961.

Governor Fortuno says Mr. Obama's visit will allow the president to understand the issues that concern Puerto Ricans, particularly the need for job creation, and the impact of a worsening drug-trafficking problem in the Caribbean.

Puerto Rico was ceded to the United States by Spain in 1898 after the Spanish-American war. The island elects its own governor and sends delegates to major U.S. party nominating conventions. It also has a non-voting representative in the U.S. Congress.