MEXICO CITY – Mexico has replaced all 700 of its customs inspectors with agents newly trained to detect contraband, from guns and drugs to TVs and other big-ticket appliances smuggled to avoid import duties.

The shake-up — part of a broader effort to root out corruption and improve vigilance at Mexican ports with new technology — doubled the size of Mexico’s customs inspection force.

The inspectors at all 49 of Mexico’s customs points were replaced with 1,400 better-educated agents who have undergone background checks and months of training, Tax Administration Service spokesman Pedro Canabal said Sunday.

He said the inspectors were not fired. Instead, government did not rehire them when their contracts expired, Canabal said.

The main focus of the overhaul is to combat tax evasion, although Mexico is also trying to seize more guns smuggled in from the United States and elsewhere that end up in the hands of ruthless drug gangs. Mexican cartels are responsible for the majority of cocaine smuggled from South America to the United States.

Canabal said the government hopes to improve its tax collection with the new system, noting that more than 40 percent of Mexico’s value-added tax is collected at customs. However, he said the main benefit will be stopping the flood of pirated and cheap goods that he said undermine Mexican industries.

Custom inspectors turned over their weapons to soldiers before leaving their posts at airports and border crossings across the country Saturday night. Enrique Torres, a spokesman for the military and federal police in the northern city of Ciudad Juarez, said soldiers were at the border crossing with El Paso, Texas, to help avoid violence during the transition.

The new agents, more than 70 percent of whom are university educated, were chosen in a “strict selection process that included psychological and toxicological checks, as well as the necessary investigations to ensure they have no criminal record,” according to a Tax Administration statement.

Canabal said the 700 who were replaced would not be banned from reapplying for their jobs, but would have to meet the new, stricter requirements. He said less than 10 percent of the ousted staffers have university degrees.

The new agents were trained in legal aspects of foreign trade and taught to use new equipment installed at border crossings, including X-ray and gamma ray machines to scan for hidden contraband. More dogs trained to sniff out drugs and other banned goods are also being added.

“We need more than just a body with a weapon,” Canabal said.

Mexico has been checking only 10 percent of the 230,000 vehicles that cross the border each day, according to the federal Attorney General’s Office.

Now, with new technology, agents will weigh and photograph every car and truck that crosses the border and run license plate numbers through a database of suspicious vehicles in the hopes of catching more hidden contraband.