A casino in Northern Mexico was set alight by two dozen gunmen, trapping gamblers inside, which resulted in the deaths of 53 people.

The fire, at the Casino Royale in Monterrey, is thought to represent one of the worst attacks on an entertainment centre in Mexico since the launch of an offensive against drugs by President Felipe Calderon in 2006.

The number of deaths is expected to climb, according to the emergency services.

This is the second time this casino has been the target of an attack in the last three months, after bullets were fired at the building in May.

Calderon tweeted that the attack was “an abhorrent act of terror and barbarism” that requires “all of us to persevere in the fight against these unscrupulous criminal bands”.

Monterrey is Mexico’s second richest city – with an economy that had a 2008 GDP of USD $102 billion, serving as a commercial centre. Although it is not a traditional centre for tourists – it does have plenty to offer visitors as a sprawling metropolis that serves as Mexico’s High Tech center. Until recently, it had long been regarded as the safest in Mexico.