Gunmen killed the leader of an environmentalist group and her 17-year-old son in southern Mexico even though 10 police officers were escorting them, authorities said.
Juventina Villa Mojica was riding up a hill on an all-terrain vehicle with her son, Reynaldo, when they were ambushed by a group of gunmen on Wednesday afternoon, the Guerrero state government said in a statement.
A local human rights group said her seven-year-old daughter was with them but escaped unscathed.
Residents of the forest area have faced threats from loggers while drug traffickers have also wreaked havoc in region. Farmers' groups have battled loggers since 1998.
Villa ended up in front of her escorts because she was using an ATV in rough terrain while five of the police officers were in a patrol car and the rest were walking, the government statement said.
"This situation allowed the assailants to surprise them since they were apparently waiting for them," it said.
The Guerrerense Human Rights Network told AFP that between 30 to 40 gunmen had been waiting for Villa, the leader of the Environmentalist Farmers Organization of the Petatlan Mountain Range.
Villa's murder took place as 45 families were due to be relocated under police protection, said Manuel Olivares Hernandez, a member of the rights network.
The government said it was increasing security to ensure the safety of the families while they are being moved away from the conflict area.
On November 14, 21 families from the municipality of Coyuca de Benitez moved to a camp in the neighboring city of Altamirano.