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

TOLUCA, Mexico — 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 on fire and fleeing. They said three of the dead appeared to be under 18, but identifications were still pending.

A statement said prosecutors were investigating private security guards for abandoning their posts at the time of the attack.

No one claimed responsibility for the attack in Toluca, about 60 kilometers (40 miles) west of Mexico City. Toluca, capital of the State of Mexico, is a city of almost a million inhabitants and is considered part of the capital’s metropolitan area, with some residents commuting to the capital to 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 disputing the possession of spaces within the markets.

The statement from state prosecutors said 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.

Toluca was 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, and while it has been largely chased out of its home state, it has found a new lease on life in the State of Mexico and neighboring Guerrero state.

The Familia Michoacana has become known for carrying out ruthless, bloody ambushes of police in Mexico State and local residents in Guerrero.

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

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

The situation in Chilpancingo remained violent Monday, as hundreds of protesters from an outlying town entered the city to demand the release of fellow inhabitants arrested on drug-related charges.

Protesters briefly blocked the main highway that leads from Mexico City to Acapulco, prosecutors said. According to video broadcast by local TV stations, the demonstrators then commandeered a police armored truck and used it to ram open the gates to the state congress building, which they entered. Legislators were apparently not in session at the time.

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