Paraguayan police beat exiled opposition leader Domingo Laino and former U.S. Ambassador Robert E. White as they arrived in Asuncion, the capital, witnesses said. White, who served as ambassador to Paraguay in 1977-79, flew with Laino from Montevideo, Uruguay, as the exile tried to defy a ban against his return imposed by the military government of President Alfredo Stroessner. "This is an open violation of human rights," White said of the attack. Laino, who has been living in exile in Argentina, was forced to stay on the plane and returned to Montevideo. White said he will meet with Paraguayan political leaders.