Warring Mexican drug gangs staking their claim over drug trade territories resulted to the deaths of 13 people despite Christmas celebrations Sunday, according to Mexican authorities.

According to Reuters, separate clashes in the districts of Guerrero and Michoacan while the nation was observing the Christian holiday. Authorities suspect that the rival groups were taking advantage of the season to mount their attacks against their opposing gangs.

In a statement issued by the office of the state prosecutor for the state of Michoacan, they reported that severed heads of six men were found right outside a business establishment in Jiquilpan, a town near the border of Jalisco and believed to be a stronghold of a Mexican criminal and drug trafficking group calling themselves the Jalisco New Generation Cartel (CJNG).

A note, according to the statement, was also found with a chilling message next to one of the severed heads signed by the CJNG's top rival the New Michoacan Family (NFM).

Meanwhile, three police officers and four other people were shot dead in the Atoyac mountains in Guerrero in the resort town of Acapulco. Authorities reported that victims were killed in a gunfight with drug dealers belonging to a still unnamed drug syndicate operating in the region.

Mexico has been shaken by escalating tension between rival drug gangs, with many criminal groups continue to fight for control of territories where they could continue to trade drugs. Even after a decade since the Mexican government began to wage war on illegal drugs, it remains to be an elusive desire to rid the country of this menace.

After he was elected into office as the president, Felipe Calderon vowed to put a stop to the drug problem in Mexico. Days after his inauguration, he launched his ambitious Operative Conjunto Michoacan or Operation Michoacan by sending more than 6000 troops to the drug-infested state to clamp down on organized crime and illegal drug trade activities. Their initial salvo yielded almost half a ton of narcotic Mexican weed, dozens of high powered weapons and no less than 2000 marijuana fields were razed to the ground.

But the Mexican drug war does not seem to be just a battle fought by the government against the cartels, but is also now a battle waged between the syndicates themselves. No less than 150,000 people have died as a result of the decades- long campaign against drugs and organized crime in Mexico. August and September 2016 became the bloodiest months in the history of Mexico in the ongoing battle against drugs and organized crime in the country.