A squad of gunmen burst onto a soccer field in central Mexico and shot to death three adults and three youths under 18, officials in central Hidalgo state said Monday.

They said others were wounded in the attack, but that local residents were loathe to provide information.

Local police chief Alejandro Rosales said the attack occurred Sunday in the town of Atotonilco de Tula, just north of Mexico City’s suburbs.

Officials did not provide a motive in the killings, but speculated they might be related to dispute between locals and people from the neighboring State of Mexico, which surrounds the capital.

In September, a similar attack on a soccer field killed four people in Morelos, south of the capital. The dead in that attack included a former mayor of the town of Yecapixtla.