Mexican police have found the tortured bodies of nine men and two women on the outskirts of the Gulf coast city of Veracruz.
The governor of Veracruz called the killings "an act of barbarity" and said they are part of a battle between drug gangs.
The killings come after Veracruz announced increased security with state and federal forces amid a wave of killings.
Governor Miguel Angel Yunes said the 11 bodies were found near a stolen vehicle and added that the killers left a sign near the corpses.
Mr Yunes did not reveal the contents of the message, but local media reported the sign said: "You want a war, you'll get a war."
The governor also said two people were killed in a confrontation with marines in the city of Veracruz on Tuesday.