MEXICO CITY, Feb. 15 (Xinhua) -- Armed men opened fire on revelers at a Valentine's Day dance in a small southern Mexican town and killed seven people, authorities said Thursday.

The massacre took place at around 1:30 a.m. local time (1930 GMT) in the community of San Juan Lachigalla, in southern Oaxaca state, as townspeople were celebrating, including family members of Mayor Rafael Melchor Ruiz, according to the daily Excelsior.

The mayor's father, son and other relatives were among the victims killed, according to the daily.

The celebration was held in the town's main square.

The farming community of San Juan Lachigalla, located just 90 km away from the state capital Oaxaca, is home to about 3,300 residents.

Raymundo Tunon, state secretary of public security, told local media that officials had no information on the attackers as yet, but that state police officers have been dispatched to the site to help in the investigation.