sentences:  In 2015, Official reports of the U.S. government and the Bureau of Alcohol, Tobacco, Firearms and explosives (ATF) revealed that over the last years, Mexican cartels improved their firearm power, and that 70% of their weapons come from the U.S.The American ATF's Project Gunrunner has as its stated purpose the stoppage of the selling and exportation of guns from the United States into Mexico, with the goal of denying Mexican drug cartels the firearms considered "tools of the trade".However, in February 2011, it brought about a scandal when the project was accused of accomplishing the opposite by ATF permitting and facilitating "straw purchase" firearm sales to traffickers, and allowing the guns to "walk" and be transported to Mexico.