(Adds details, quotes) By Mary Milliken SAN DIEGO, Oct 2 (Reuters) - The U.S. government on Tuesday showed its best results in the war against drugs in 20 years but said it has yet to prove it can significantly reduce cocaine and other narcotics distribution over the long term. Reports of cocaine shortages in 37 U.S. cities, leading to a 24 percent jump in its street price, are important milestone for the anti-drug effort, White House 'drug czar' John Walters told a news conference. "But the real challenge is: can we sustain it?" said Walters, director of the National Drug Control Policy. The statistics were announced before the United States launches what is likely to be a substantial aid plan to combat drug distribution in Mexico and along the border, where 90 percent of the cocaine to the United States enters. Mexican President Felipe Calderon and U.S. President George W. Bush are hammering out details of the plan, which U.S. officials said could be worth $1 billion initially and grow over time. Walters gave no details but said the two leaders could announce a deal soon. Walters credited Calderon's crackdown on drug cartels since taking office in December and joint military-police sweeps in nine Mexican states for part of the success against cocaine trafficking across the United States. Mexico has also extradited some of its biggest traffickers to the United States, like Osiel Cardenas, head of the Gulf Cartel based just south of Texas. "Mexico has always extradited people but never at that level," said Drug Enforcement Administration official Jim Craig. TARGETING BORDER 'GATEKEEPERS' In addition to targeting the mega cartels in Mexico, like the Gulf Cartel and an alliance of traffickers from Sinaloa state, Walters said enforcement agencies were working to break down border "gatekeepers" who collude with the cartels. "They control ports of entry, the so-called 'plazas'," said Walters. "They have family, sometimes criminal gangs that have been there for a long period of time on both sides of the border moving money, guns, drugs, trafficking of people." Walters said he recognized that, despite recent success, the border continues to be a violent place where officials from both sides are attacked, gang members kill rivals and Mexican citizens do not see much reduction in danger. But Walters said the only way to improve security was to "destroy the business." In addition to the shortage of cocaine on the streets, the U.S. government highlighted other trends such as workplace drug testing data showing the lowest level of positives since 1992 and fewer cocaine-related emergencies in hospitals. Statistics also show progress against methamphetamine trafficking across the border and a 37 percent rise in the price of the drug that has hit small U.S. towns hard. Walters said the benchmark for anti-drug success was the destruction of the French Connection heroin route from France to New York City which slashed heroin consumption and kept it low for decades. "We have some much larger problems across multiple drugs from the last 20 years," said Walters. "But we are trying to see if we can create the same phenomenon."
