The daughter of Cuba's vice president has defected from the communist-run island and now lives in Tampa, Florida, the site of the Republican National Convention, a newspaper reported.

Glenda Murillo Diaz, 24, daughter of Vice President Marino Murillo, crossed over into Texas from Mexico, according to a report in the online version of US Spanish-language newspaper El Nuevo Herald.

Cubans who set foot on US soil are allowed to remain in the country as part of Washington's "wet foot, dry foot" policy. Cubans intercepted at sea are returned to Cuba.

The cause of Diaz's defection is not yet known, but the newspaper said the incident represents "a vote of no confidence in the economic reforms (President Raul) Castro has ordered, and that her father has a mandate to implement."

Cuba's vice president, an economist by trade, is known as the "reform czar."

Thousands of delegates have descended on Tampa for the Republican convention, which began Monday and will culminate in the formal nomination of Mitt Romney to take on US President Barack Obama in the 2012 presidential race.