One day before President Barack Obama travels to Mexico, the administration named Alan Bersin to lead efforts to police the United States' southern border and announced a new clampdown on Mexican drug gangs, according to dpa. Bersin, who served in a similar capacity under former president Bill Clinton, "will lead the effort to make our borders safe while working to promote commerce and trade," Homeland Security Secretary Janet Napolitano said during a visit to El Paso, Texas. The White House meanwhile said it was sanctioning three Mexican drug cartels, allowing the Treasury Department to seize and block financial assets of the Sinaloa Cartel, Los Zetas and La Familia Michoacana. Obama will meet with Mexican President Felipe Calderon Thursday. The growing death toll in Mexico, where the military has been enlisted to fight the drug gangs, and US aid to the effort is expected to be at the top of their agenda. White House spokesman Robert Gibbs said freezing the assets of drug cartels was part of that effort. "Today's action underscores the US government's support for President Calderon's courageous attack on the cartels and our attempts to attack the financial underpinnings of Mexico's cartels, believed to generate billions of dollars annually," Gibbs said.