Police in Mexico say they have found three decapitated bodies on a rubbish dump in Tijuana, in the latest incident of gang-related violence.
The victims were found with their hands tied, along with messages referring to drug-trafficking. Their heads, found nearby, appear to have been burnt.
Officials say the incident appears to be a settling of scores by cartels.
Recent drug-related violence has included kidnaps and murders that sparked public outrage.
The bodies had messages written on their backs threatening Tijuana's powerful Arellano Felix drug cartel.
Since Monday, more than 20 other suspected drug killings have been reported, including the murder of five people who were shot dead on a ranch in the northern border state of Chihuahua.
Last week, Mexico's political and security leaders launched an emergency programme to try to combat the rising wave of violence.
There have already been more than 2,700 drug-related deaths this year.
Measures include sacking corrupt police officers, two new prisons for kidnappers and strategies to combat money-laundering and drug-trafficking.
The national security pact was signed by prosecutors and leaders from across the political and regional spectrum.
The country has overtaken Colombia and Iraq for the number of kidnappings.
Anti-kidnap marches are planned for 30 August, a sign of the growing public fury.