At least 20 people have been killed and eight injured in an attack on a casino in the northern Mexican city of Monterrey

Armed men broke into the building and set it alight, but it is not clear whether the fire was caused by grenades, or an arson attack. Firefighters had to free dozens of people trapped by smoke and flames. Monterrey has seen a surge in violence by rival drugs gangs. The city is being disputed by two rival drug cartels - Los Zetas and the Gulf cartel.