Mexican President Felipe Calderon has warned that corruption among American officials may be making it harder to deal with drug-trafficking between Mexico and the US. Mr Calderon said violence in the border city of Juarez had fallen by 73% in the month since he sent 7,000 extra troops there. There has been open warfare in Juarez for more than a year; last year, 5,600 people were killed in drug-related attacks in Mexico, many in Juarez. President Calderon said it was impossible to smuggle [tons] of cocaine into the United States without the complicity of some American authorities. There is trafficking in Mexico because there is corruption in Mexico," he told the BBC. "But by the same argument if there is trafficking in the United States it is because there is some corruption in the United States... It is impossible to pass tonnes of cocaine to the United States without the complicity of some American authorities." The situation along the border is very sensitive politically, and although the White House may wonder privately whether there is some corruption among some American customs, immigration and police officials, it is unlikely to admit it publicly.