Local police in the northern Mexican border city of Tijuana have been ordered to hand in their guns.
The guns will be inspected by federal officials
The move is part of an operation by soldiers and federal police to crack down on drug traffickers.
The guns will be inspected by federal officials, who are investigating allegations that some local officers have been involved in drug smuggling.
Police are refusing to patrol unarmed, reports say. Gang violence left more than 300 dead in Tijuana last year.
Earlier this week, the government announced it was sending more than 3,000 soldiers and police to the Tijuana to help fight drug trafficking and gang violence.
Interior Minister Francisco Ramirez Acuna said the Tijuana operation would be backed by 28 boats, 21 planes and nine helicopters.
The city, across the border from San Diego in California, is a major entry point for drugs into the US.
This is the second such federal operation ordered by President Felipe Calderon since he took office last month.
In December, federal officials carried out a crackdown in the western state of Michoacan, which is also hard hit by drug-related violence.
Drug gangs are blamed for more than 2,000 deaths in Mexico in 2006.