MEXICO CITY (AP) — Mexican authorities say 12 people have died in the central state of Puebla in a string of shootings being investigated as possible score-settling by rival gangs of fuel thieves.

The state prosecutor's office reports Tuesday that three men and a woman were slain at a hospital in the state capital. Another man was shot dead while driving in the suburb of Chachapa. And two more were killed while riding in a pickup truck in the municipality of Amozoc de Mota, which contains Chachapa.

In a separate statement late Monday, Puebla prosecutors said gunmen in an SUV shot dead five people who were drinking on a lot around midday in Tlaltenango.

Fuel pipeline theft is a growing problem in Mexico, with regular shootings between gangs and sometimes police or soldiers.