Rich Mexicans, terrified of soaring kidnapping rates, are having tiny radio transmitters planted under their skin so they can be quickly tracked and rescued.

Hundreds of people, including a growing number of middle-class Mexicans, are buying the tiny chip designed by Xega, a Mexican security firm.

Kidnapping jumped almost 40 per cent between 2004 and 2007 in Mexico, which has surpassed conflict zones like Iraq and Colombia to register the highest kidnapping rates in the world, according to a recent study.

This week the administration of President Felipe Calderon pledged to develop an anti-kidnapping strategy within six months, after a meeting with the country’s top judges, congressional leaders, governors and mayors.

The recent kidnapping and murder of Fernando Marti, 14, the son of a well-known businessman, sparked widespread outrage, After allegations of police involvement in Mr Marti's kidnapping, his father called on politicians to act to curb increasing crime.

"If you think this task is impossible, resign," Alejandro Marti told the meeting, adding that they would be contributing to corruption if they maintained their posts and failed to act. "We have to recover confidence in our institutions, in our state, in our country."

Xega injects the crystal-encased chip, the size and shape of a grain of rice, into clients’ bodies with a syringe. A transmitter in the chip then sends radio signals to a larger device carried by the client with a global positioning system inside.

A satellite can then pinpoint the location of a person tied up in a safe house or stuffed in the trunk of a car.

Most people get the chips injected into their arms between the skin and muscle where they cannot be seen. Customers who fear they are being kidnapped press a panic button on an external device to alert Xega, which then calls the police.

“Before, they only kidnapped key, well-known economically successful people like industrialists and landowners. Now they are kidnapping people from the middle class,” said Sergio Galvan, Xega’s commercial director.

The company designed global positioning systems to track stolen vehicles until a company owner was kidnapped in broad daylight in 2001. Frustrated by his powerlessness to call for help, Xega adapted the technology to track stolen people.

Cristina, 28, who did not want to give her last name, was implanted along with seven other members of her family last year as a “preventive measure.” “It’s not like we are wealthy people, but they’ll kidnap you for a watch. ... Everyone is living in fear,” she said. The chips cost $4,000 plus an annual fee of $2,200.

Most kidnappings in Mexico go unreported, many of them cases of “express kidnapping” where the victim is grabbed and forced to withdraw money from automatic cash machines.

Official statistics show 751 kidnappings in Mexico last year, but the independent crime research institute ICESI says the number could have exceeded 7,000. In Mexico City alone, official figures showed 323 reported kidnappings in the first half of this year, approaching the figure of 438 for the whole of 2007.

The Government has promised to build two new maximum security prisons with a special area for kidnappers within two years, trying to address concerns that new gangs arise in low security penitentiaries.

All organised crime suspects will be moved to existing high security prisons within 30 days. A purge of corrupt police, some of whom are said to afford protection to criminals, will also be carried out.

Xega sees anti-kidnapping devices as a growth industry and is planning to expand its services next year to Brazil, Colombia and Venezuela.

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