Mexico quinceanera
Quinceanera, or the "coming of age" celebration is a tradition dating back to the Spanish colonial era when 15- and 16-year old girls made their official "debut" in society Jorge Dan Lopez/Reuters

At least nine people were shot dead at a teenage girl's 15th birthday party in Mexico's southwestern Guerrero state. The mass killing took place on 29 January at the girl's "quinceanera", or coming-of-age celebration in Cundancito, western Guerrero.

Two minors were among the dead and officials have not released their ages. Seven men aged between 18 and 50 were killed in the violence. Originally, 11 people were reported dead, but this number has since been revised.

It is unclear whether any arrests have been made over the incident. According to family accounts reported by the EFE news agency, the violence may have broken out following a disagreement between two families at the celebrations.

Speaking at a news conference on 31 January, state governor Hector Astudillo told reporters: "There was a problem at a 15th birthday party, and according to the information we have, 11 people were killed". According to Astudillo, officials tried to access the scene following the massacre, but came under fire.

Guerrero is Mexico's bloodiest state and impunity is rife. Violence often erupts between rival drug cartels in the region. According to a 2015 report entitled Broken Justice, only one in 15 homicides in the region lead to a conviction. Over the course of 24 years (1990 - 2014), the state's human rights commissioner documented 90 cases of "enforced disappearances", but nobody has ever been indicted.

During the weekend, a tourist was murdered after coming under ambush in Guerrero on 31 January, according to Fox News Latino. The state received international media attention in 2014 after 43 students forcibly disappeared on 26 September. The students came under police fire and were handed over to a drug cartel, which reportedly murdered them.

According to figures compiled by La Jornada newspaper, at least 324 people were murdered in Guerrero between October and December 2015. Most of the deaths were drug-related.