At least eight people were killed Tuesday when a group of men tossed Molotov cocktails into a bar in the tourist friendly Mexican town of Cancun, officials said.

Authorities said six to eight men entered the Castillo de Mar bar and threw homemade bombs, killing six women and two men who were inside.

Investigators said they do not know of a motive for the attack, but the bar was reportedly the victim of two extortion attempts, allegedly by the Zetas drug cartel.

"The death of eight people is confirmed. Six on site -- including four women -- and two others in hospital, also women," prosecutor Francisco Alor Quezada, from the southeastern state of Quintana Roo, told AFP.

Local media reports said the attack happened at around 1a.m. local time Tuesday. It set off a fire which destroyed the bar, which is in a residential area not frequented by tourists, officials said.

The names of the victims were not released, but they were believed to be locals and not tourists, Quintana Roo state attorney general's office spokesman Felix Canul told Fox News.

The brutal Zetas, first set up by former paramilitaries in the 1990s, have grown in force since splitting off from the powerful Gulf gang, whom they are now fighting for control of drug trafficking routes.

The group also is suspected in last week's massacre of 72 migrants in northeast Mexico and many kidnapping, killing and extortion cases.

Cancun has seen sporadic attacks and gruesome discoveries of bodies in wells and graves as violence has escalated since President Felipe Calderon deployed tens of thousands of soldiers to take on organized crime gangs in 2006.

More than 28,000 have died in drug-related violence nationwide since then, according to official figures.

Newscore contributed to this report.