The United States is pulling more than half its diplomatic personnel out of Cuba and warning Americans not to visit in response to mysterious sonic incidents that sickened 21 embassy staffers and their families, senior U.S. officials said on Friday. In addition to ordering all non-essential personnel and their families to leave, the U.S. will also suspend the processing visas in Cuba, the officials said. Cuba has repeatedly denied any involvement in the baffling incidents, and the U.S. has still not determined who is behind them. Sen. Patrick Leahy, an advocate for closer relations between the U.S. and Cuba, said in a statement that the culprit "obviously is trying to disrupt the normalization process."