Mexico's government plans to search 10 percent of all vehicles entering the country from the United States in an effort to curb arms smuggling, the attorney general said Tuesday.

Most illegal weapons in Mexico come from the United States, according to officials in both countries. Many end up in the hands of powerful drug cartels who supply most of the cocaine entering the United States from South America.

Attorney General Eduardo Medina said the stepped up vehicle searches would start soon at Mexican custom checkpoints, though he did not give an exact date.

He said an average of 230,000 vehicles across into Mexico from the U.S. each day. The number searched changes throughout the year, and varies with each crossing point.

"Soon, at least 10 percent of vehicles crossing from north to south will be subjected to obligatory searches at customs," Medina said.

Michael Sullivan, the acting director of the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives, said last month that investigators have traced 90 to 95 percent of weapons seized in Mexico to the United States.

Mexico seized more than 10,763 guns between December 2006 and August 2008, most of them assault rifles, according to a recent report from the Attorney General's Office. More than 1,400 grenades also were confiscated.

"What's clear, as we have often told many lawmakers in the U.S. Congress, is that the Second Amendment was not designed to arm criminal groups overseas, as is in fact occurring," Medina said, referring to the amendment in the U.S. Constitution on the right to bear arms.

In general, only law-enforcement officers or military personnel can legally possess guns in Mexico.

The stepped up vehicle searches come as Mexico's government struggles to reverse a surge in violent crime, much of it tied to the drug trade. Mexican police often complain of being outgunned by drug cartels, whose fierce attacks have prompted terrified officers to walk off the job.