The police chief, the mayor and a local politician of a small town on the American side of the US-Mexico border have been charged with gun running.
Prosecutors say the officials from Columbus, New Mexico, bought some 200 guns which they allegedly planned to sell to drug cartels in Mexico.
The officials were arrested along with seven other locals on Thursday morning.
Mexican President Felipe Calderon has urged the US to do more to stem the flow of illegal weapons to his country.
Prosecutors said Columbus Mayor Eddie Espinoza, police chief Angelo Vega and Columbus trustee Blas Gutierrez "increased the risk of harm that the people of Columbus face every day by allegedly using their official positions to facilitate and safeguard the operations of a smuggling ring... exporting firearms to Mexico".
The arrests were made at eight separate locations, including Columbus's police station.
The defendants are accused of falsely claiming they were buying weapons for themselves, when they intended them for sale to others.
Prosecutors said the suspects had bought arms favoured by members of Mexican drug cartels, including AK-47-type weapons and American Tactical 9mm caliber pistols.
They are due to appear in federal court in Las Cruces, New Mexico, on Friday.