Mexico City  - Unidentified attackers shot to death five people Monday at a bar in the northern Mexican city of Ciudad Juarez, the authorities of the state of Chihuahua confirmed.

The attack happened early of Monday at the bar Gabino's, where four people had been killed in a similar incident earlier this year. The motive behind the killings was not known, and no one was arrested in connection with them.

Violence in Ciudad Juarez mainly involves rival drug gangs, the authorities say. It leaves an average of 10 people dead everyday in the border city that is a crucial gateway to the lucrative US drug market. The Sinaloa drug cartel is fighting a bloody war against the Juarez cartel and its hitmen squad, La Linea, for control of routes through Ciudad Juarez.

Drug violence has left more than 5,000 dead in Mexico since the beginning of the year. dpa