MEXICO CITY: Assailants killed 15 inhabitants of an indigenous village in southern Mexico that has been plagued by local disputes, authorities said on Monday, in one of the most brutal attacks to shake the countryside in recent years.

State prosecutors in the state of Oaxaca said the bodies of 13 men and two women were identified as victims of the attacks over Sunday night and Monday morning in the municipality of San Mateo del Mar, east of the Pacific port of Salina Cruz.

The San Mateo del Mar municipal government said in a statement that the attack was orchestrated by at least six armed people with the support of a suspected local crime boss.

In a separate statement, Oaxaca state prosecutors said investigations are under way into what sparked the violence in Huazantlan del Rio, a local village of Ikoots indigenous origin. Officials are still investigating whether the attackers had guns.

The two women killed had been protesting against abuses by one of the suspected attackers, who described himself as a representative of Huazantlan del Rio, the municipal government said.

The conflict stemmed from road blocks organized in recent weeks by people claiming to represent Huazantlan del Rio authorities who wanted to stir up trouble for their own ends, the municipal government said, without giving more details.

The attackers tortured and burned alive a number of their victims, the municipal government said. Photos of some of the victims’ partly burned corpses were published on social media. One of the dead men appeared to have been beaten with bricks.

A state official said the photos were genuine.

No arrests have yet been made, the official added.

San Mateo del Mar lies on a coastal spit, and the area has suffered from territorial disputes and conflict over rights of way for many years, according to the state official.

The area around the isthmus of Tehuantepec has also become known in recent years for land disputes over infrastructure projects.