Masked men burn a market in a Mexican city plagued by gang violence, killing 9

Masked gunmen set fire to a public market in the central Mexican city of Toluca on Monday, killing nine people, authorities said.

Prosecutors said the attackers arrived, opened fire, and then doused part of the market with a flammable substance before setting it ablaze and fleeing.

Prosecutors said in a statement that they were investigating private security guards who reportedly abandoned their posts at the time of the attack.

Officials said three of the dead appeared to be younger than 18, but identification of the victims was still pending.

No one claimed responsibility for the attack Monday in Toluca, about 40 miles west of Mexico City.

A city of almost a million inhabitants, Toluca is considered part of the capital’s metropolitan area, with some residents commuting to the capital for work.

Fires at public markets in Mexico are often set by gangs demanding protection payments from vendors, but some have also been set by vendors in disputes over spaces in the markets.

Prosecutors in the state of Mexico, where Toluca is located, said in the statement that “one of the first lines of investigation is that events may have been related to internal disputes over the possession of commercial spaces” at the market.

The attack came as prosecutors in the neighboring state of Guerrero confirmed that over the weekend, four taxi drivers had been shot to death, and at least one of their cars set on fire, in and around the state capital of Chilpancingo.

That city was the scene of horrific violence in late June, when dismembered pieces of seven bodies were left on a downtown street along with a threatening message from a gang.

Guerrero state is the site of a bloody turf war between La Familia Michoacana and several other gangs, one of which is believed to be responsible for recent killings in Chilpancingo.

Toluca was also set on edge last week by the discovery of at least two hacked-up bodies, and signs claiming responsibility by the violent Familia Michoacana drug cartel.

The gang originated in the neighboring state of Michoacan in the early 2000s. It has been largely chased out of its home state, but has found a new lease on life in the states of Mexico and Guerrero.

La Familia Michoacana has become known for carrying out bloody ambushes of police in Mexico state and residents of Guerrero.