MEXICO CITY, October 31 (RIA Novosti) - Fifteen people, including a prominent farmworker leader and his three children, were killed at an isolated ranch in northern Mexico, local television said on Saturday.

The bodies of Margarito Montes Parra and his supporters were found riddled with bullets in trucks at a ranch in Sonora, a state bordering the United States, television reports said.

Sonora official Antonio Jose Rodriguez said the farmers seemed to have tried to escape a chase at the farm.

No group has so far claimed responsibility for the killings. Mass murders of farmers are common in Mexico, where drug gangs control large areas. Farmers are often forced or paid to grow opium poppies for drug gangs.

President Felipe Calderon ordered massive military and police operations nationwide after taking office in 2006, pledging to defeat powerful drug gangs before his term ends in 2012.

Despite the government's reported success in detaining drug lords, drug-related violence continues to increase.