Monterrey and the state it is situated in – Nuevo Leon – has become one of Mexico’s most violent places after a turf war broke out between two major drug cartels.

More than 600 people have been killed in the last year; as a result the state and authorities have launched an unprecedented war against drug gangs.

And as Al Jazeera’s Mariana Sanchez reports from Monterrey, fear and frustration have gripped the city.