( CNN ) -- Mexico 's president called on U.S. officials to stop gun trafficking across the border Thursday , saying the move would be the best thing Americans could do to stop brutal drug violence . `` The criminals have become more and more vicious in their eagerness to spark fear and anxiety in society , '' President Felipe Calderon said . `` One of the main factors that allows criminals to strengthen themselves is the unlimited access to high-powered weapons , which are sold freely , and also indiscriminately , in the United States of America . '' Speaking in Ciudad Juarez , the border city across from El Paso , Texas , that has become Mexico 's murder capital , Calderon said a dramatic increase in violence in Mexico was directly connected with the 2004 expiration of the U.S. assault weapons ban . The message was familiar . The Mexican president has asked U.S. lawmakers to renew the ban on assault weapons before , most notably in a 2010 speech to the U.S. Congress . But the backdrop Thursday was dramatically different . Calderon stood in front of a massive new sign , constructed with tons of decommissioned arms . `` NO MORE WEAPONS , '' the sign said -- in English . Americans on the other side of the border are the intended audience , Calderon said . `` From here , from Ciudad Juarez , on the border of Mexico and the United States , we say , 'No more weapons . No more weapons to Mexico , ' '' he said . Thursday 's speech came as a U.S. Congressional inquiry continues into `` Operation Fast and Furious , '' an operation run by U.S. federal agents . Authorities have said the operation was intended to track the flow of illegally purchased American guns to the Mexican cartels -- but in practice , agents from the Bureau of Alcohol , Tobacco , Firearms and Explosives allowed so-called straw buyers to take weapons across the border without being intercepted . Calderon praised U.S. President Barack Obama 's efforts to deal with the `` very sensitive issue '' of assault weapons , noting that officials in his administration had done more than previous leaders to investigate and block illegal weapons trafficking to Mexico . `` They have taken positive steps , but we all know that unfortunately it is not enough , and we can not stop here , '' he said . Out of 140,000 weapons Mexican authorities have seized since Calderon declared a crackdown on cartels at the beginning of his presidency , 84,000 were high-powered assault weapons , Calderon said . More than 47,000 people have been killed in drug-related violence in Mexico since December 2006 , according to government statistics . During his Thursday speech , Calderon looked toward the border and said he had a message for Americans . `` We need your help to stop this violence . We need you to reduce your consumption of drugs and to dramatically reduce the flow of money to criminal organizations in Mexico , '' he said . `` But beyond the topic of drugs , the best way that you , the American people , can help reduce the violence in Mexico is through legislation that has already been in force in the United States , blocking the inhumane weapons trafficking into our country . '' CNN 's Rey Rodriguez , Eduardo Aragon and Ariel Crespo contributed to this report .
Calderon says criminals have `` unlimited access to high-powered weapons '' He stands before a new sign in Ciudad Juarez that says , `` NO MORE WEAPONS '' The president says Mexico needs U.S. help to stop the violence .