The United States sanctioned three top Cuban officials on Thursday, the latest in a string of steps in reaction to the island's recent protest crackdown on anti-government demonstrators.The Treasury Department said in a statement that the sanctions targeted two top defense ministry officials for their roles in repressing rare rallies in the communist-ruled country, where hundreds were detained."We will continue to hold responsible those who help the Cuban regime to perpetrate human rights violations," said Andrea M. Gacki, director of the Treasury's Office of Foreign Assets Control."Today's action exposes...