Glenda Murillo Diaz, 24, considered by some to be a successor to Cuban President Raul Castro, crossed the border from Mexico to Laredo, Texas, sometime around Aug. 16, sources told the newspaper, which reported the defection Monday.
Marino Murillo, an economist and former military officer, is vice president of the ruling Council of State and is known as Cuba's "reforms czar," The Miami Herald said.
Glenda Murillo Diaz did not receive a U.S. visa to visit her relatives, the sources told El Nuevo Herald.
Exploding whale video goes viral on Internet
Texas principal bans speaking Spanish, stirs controversy