Gunmen killed four people Tuesday in a neighborhood in the southern part of Mexico City, the Federal District Attorney's Office said.

The murders occurred around 2:00 a.m. on La Paz street in Barrio San Ignacio, a neighborhood in the borough of Iztapalapa.

Jose Octavio Sanchez Juarez, Alfredo Moreno Ledezma and Ivan Israel Peralta Frias were pronounced dead at the scene, while Pablo Reyes Mosco, who was also hit by the bursts of gunfire, was pronounced dead on arrival at a hospital.

Crime scene investigators found 31 bullet casings from weapons of different calibers at the site.

Investigators are gathering evidence to try to track down the gunmen in what appears to be a settling of scores between rival gangs, the DA's office said.

Crime is one of the biggest problems in Mexico, where more than 50,000 people have died in drug-related violence since President Felipe Calderon declared war on the country's powerful cartels shortly after taking office in December 2006. EFE