Mexican soldiers patrol the perimetre of the Sanctions Enforcement Centre at Nuevo Laredo [Reuters]

At least seven prisoners have been killed and 59 others escaped following a prison riot in the Mexican town of Nuevo Laredo, on the border with the United States, officials have said.

Mexican authorities have ramped up security at the Sanctions Enforcement Center where prisoners serving sentences for drug trafficking and gang charges overpowered the guards, the Tamaulipas state government said in a statement.

"The situation is currently under control," the statement said.

Of the 59 people who fled, 35 were being held on federal charges, which include drug trafficking and involvement in armed gangs, state officials said according to AFP.

Five prison guards also fled on Friday, the official statement said.

Despite Mexican President Felipe Calderon's pledge to reform the prison system, Mexico's jails are rife with corruption and poor conditions.

Last year nearly 350 inmates escaped from nine prisons in the north-eastern state of Tamaulipas. Authorities say there are some 7,800 inmates in Tamaulipas prisons, including 1,238 at Nuevo Laredo's Sanctions Enforcement Center.

Tamaulipas is the epicenter of a battle between two violent drug cartels -the Gulf cartel and the Zetas, made up of ex-commandos-for control of lucrative smuggling routes into the United States.

Some 37,000 people have been killed since Mexico launched a massive military crackdown in December 2006 on powerful drug cartels.