Four men were shot dead by a group of gunmen at their house on the limits of Tlalnepantla, a city in Mexico state, and the Mexico City borough of Azcapotzalco, officials told Efe Tuesday.

Several armed subjects arrived around 11:40 p.m. Monday "at 117 Lazaro Cardenas street in the Santa Maria Tlayacampa district" in an SUV and "started firing on the people who were there," a Tlalnepantla city government official said.

One of the victims fell in the doorway and "the killers went inside the dwelling and opened fire on the other three," the city official said.

Neighbors called police, who responded to the shooting along with crime scene investigators from the prosecutor's office.

The crime scene investigators gathered evidence and removed the four bodies from the house.

The victims have not been identified and investigators do not have a motive for the multiple murders, but "it is believed that it was a settling of scores between rival gangs," the city official said.

Tlalnepantla is in Mexico state, which surrounds the Federal District and forms part of the Mexico City metropolitan area.

The war on drugs launched by former President Felipe Calderon, who was in office from 2006 to 2012, left about 70,000 people dead, or an average of 32 per day, in Mexico, officials say.

Calderon, of the conservative National Action Party, or PAN, deployed thousands of soldiers and Federal Police officers across the country to fight drug cartels.

President Enrique Peña Nieto, of the Institutional Revolutionary Party, or PRI, has continued the strategy implemented by Calderon of taking on the cartels, but he has also called for bolstering intelligence capabilities and attacking criminal organizations' entire structures, not just kingpins. EFE