Washington’s efforts to combat narco-corruption in the region reached the highest levels of government in the Dominican Republic, where two military generals close to the president lost their visas to travel to the United States due to alleged ties to drug traffickers.

President Leonel Fernández’ top military adviser Héctor Medina Medina and border security chief General Manuel de Jesus Florentino Florentino lost travel visas under the rule that allows the government to target officials suspected of corruption, a U.S. government official confirmed.

In at least one case, the high-ranking military leader was returned to the Dominican Republic after arriving in the United States, the source said. One of the generals lost his rights to visit as long as a year ago, but the information surfaced this week amid a heated presidential campaign where the first lady is a candidate for vice president.

The news, first reported Tuesday by Univision television network, said that two other top Fernández advisers had also lost their travel visas — but those men arrived in Miami on Friday and denied the account.

“Impossible,” said Gen. Rafael Guzmán, the former national police chief who serves as a senior presidential security adviser. “On the contrary, I invite you go to the Dominican Republic to see that under my tenure was when we decidedly began to combat drug trafficking for the first time in the history of the Dominican Republic.”

Guzmán was at Florida International University for a presentation about an anti-crime program he developed with Prof. Eduardo Gamarra, who works closely with the president. He said he travels frequently to Miami and has never been questioned about his visa.

While at least one U.S. embassy cable released by WikiLeaks suggested that diplomats in Santo Domingo felt confident that Guzmán was cracking down on corrupt police, cables show the embassy had serious concerns about Medina and Florentino as far back as 2008.

When Medina was up for a promotion to minister of defense, the cable said his “potential promotion prompted serious U.S. concern.” Medina was not elevated, but the embassy was dismayed to see him remain as chief of the Presidential Military Aide’s Corps, where he would “continue to have a powerful influence on the President’s military decisions.”

More serious concerns were raised about the retired general in charge of the border, who was a top intelligence official and former secretary of the armed forces. The embassy had a “frank discussion” with the president “concerning questions about Florentino’s competence and personal integrity,” the cable states. The embassy suggested he had ties to drug trafficker Quirino Paulino, and said working at the Haitian border would present Florentino with more “opportunities for graft.” The president, the cable said, suggested it was too politically volatile to move him, and he would do it some other time.

The Dominican Republic has become a major transshipment point for Colombian cocaine, which moves through the country with the help of corrupt top members of the military. Lower level police are often known to control trafficking on the streets.

Last year, The Miami Herald reported that the Armed Forces had fired 2,300 soldiers in the three prior years, including two generals and six colonels. The specialized drug police had dismissed more than 400 of the 2,000 officers.

“This situation with the visas of top people in government is very worrisome,” said Autonomous University of Santo Domingo Prof. Julio De La Rosa, who runs an anti-corruption civic organization. “The mere suggestion that people close to the president are under investigation should be enough for him to separate himself from them. But instead, he does the opposite.”

Fernández attended public events this week with the implicated advisers. The president’s spokesman Rafael Nunez did not return calls seeking comment.