An estimate total of 27 people have been killed in two seperate drug cartel-like incidents in Mexico [GETTY]

At least 17 people have been killed in a bar massacre in northern Mexico, believed to be linked to a turf war between rival drug trafficking gangs.

Riflemen opened fire on drinkers and employees at the bar in the city of Monterrey on Friday, a state forensic investigator said.

The medical examiner's official, speaking on condition of anonymity, said his office had recovered 17 bodies, including those of women, from the crime scene.

Police sources would not confirm the number of dead people with the Associated Press news agency and referred AP to local prosecutors, who were not giving an official account of the shooting.

Mexican media reported 20 killed while the newspaper Reforma reported that five more people were wounded.

Monterrey, a major industrial hub, has seen a rise in violence since the Gulf and Zetas cartels began fighting for control of the drug trade there two years ago.

Federal police spokesman Jose Ramon Salinas said that high-powered weapons used in the shooting indicated it might have been a drug cartel confrontation.

Police sealed off the crime scene, which was still heavily guarded by the Mexican army and federal police by early Saturday morning.

Other downtown businesses appeared closed earlier than usual after news of the massacre broke, said AP.

Killings in Mexico City

In another incident further south of Mexico, 11 human bodies were found near a water-well on the outskirts of the city.

Police are investigating the bodies of ten men and a woman who had been shot with high-powered rifles.

The bodies were found on Friday piled near a water well in Valle de Chalco, on the eastern edge of Mexico City, authorities said.

Police have not linked the killings with drug gangs but the nature of the killings mirrored drug cartel tactics frequently seen in regions controlled by drug cartels.

Some of the bodies were blindfolded and had their hands tied, said a spokesperson for the Mexico state police.

State officials said police found another body nearby a few hours later but could not confirm it was related to the mass attack.

The police spokesperson said he didn't know if the victims were shot at the scene or dumped at the site.

Drugs in capital

The capital region has been largely spared the widespread drug violence that grips parts of Mexico.

But, some poorer areas of the sprawling metropolis of 20 million people have begun to see killings and decapitations committed by street gangs that are remnants of splintered drug cartels.

Drug consumption has grown dramatically in the past decade in the capital, health officials said.

Authorities said the violence around Mexico City stems from an increasingly lucrative local drug market, with killings mostly related to fighting among rival low-level drug dealers.

Source: Agencies