There's been yet another grisly discovery of chopped up bodies in Mexico, as the battles between drugs cartels intensify and the government appears to be struggling to contain the dangerous situation.

This is the scene as the 18 corpses, all of them headless, arrived for forensic examination. They were found stuffed into two cars along the highway in the country's second largest city, Guadalajara. This paramedic told news crews "In one car, there are mutilated people. In the other, we weren't able to proceed because the car was completely full. None of the doors could be opened. The bodies were covered up. Some of them were mutilated and some were whole."

There was also a note signed by the Zetas cartel. They're a gang led by ex-Mexican soldiers who've been blamed for some the worst killings in the drugs war.

The deaths come just a few days after the bodies of 4 people – two of them journalists - were found in bags and dumped in a canal in Boca del Rio. They'd apparently written stories challenging the gangs and one of the victims was said to have received death threats weeks earlier. On the same day another 14 bodies were found dismembered in the border city of Nuevo Laredo, and 9 people were discovered hanging from a bridge there.

It seems the violence is in full flow with no signs of the government being able to contain it. In the last five years, more than 50,000 people have died in drugs battles in the country.