At least six people died and five were wounded when a grenade exploded in a casino in this northern Mexican city, and several people were trapped by the fire that broke out after the attack, officials said.

Initial reports were that two people had been killed and five wounded, but authorities later said that five women and one man died in the blast and the local press was reporting that there were eight fatalities.

The attack at the Casino Royal, located on the corner of Jesus Maria Fernandez and San Jeronimo streets in the western part of the city, was reported to the State Investigations Agency about 3:50 p.m. (2050 GMT), an official told Efe.

One of several armed men threw the grenade into the casino, where it exploded.

Law enforcement authorities are actively scouring the area seeking the perpetrators, while teams of emergency aid workers and firefighters are working to rescue the trapped people and to put out the fire.

Less than 24 hours before the strike, unknown attackers threw a grenade into another casino in the neighboring city of Saltillo, in the state of Coahuila.