MEXICO CITY (Reuters) - Gunmen ambushed Mexican federal police agents on Monday killing four and wounding seven in Guerrero, one of the country’s states that is most plagued by drug-violence, the government said.

The agents were attacked during an operation in the municipality of San Miguel Totolapan, the federal attorney general’s office said in a statement.

One criminal suspect was killed and three were wounded, the office said.

State authorities said soldiers and state police were searching for the gunmen. San Miguel Totolapan is a fiefdom of Los Tequileros, one of the bloodiest criminal gangs in Guerrero.

Violence has spiked in Guerrero over the past decade as a growing number of criminal gangs vie for control of crops of opium poppies and for drug-trafficking routes.