Mexico has made an official request for more information about a secret U.S. government operation to allow smugglers to take nearly 1,800 guns into Mexico in an effort to track them to drug trafficking organizations. The operation, code-named "Fast and Furious," was run by the Bureau of Alcohol, Tobacco, and Firearms (ATF), in spite of objections from its own agents. Assault weapons and high-powered sniper rifles were among the guns smuggled in to Mexico over a period of 15 months. Some of the 1,765 weapons have since been linked to crime -- including the murder of a U.S. border patrol agent in December. Fewer than 800 of the guns have been recovered.