A car bomb was detonated via remote control in downtown Monterrey, Mexico, in an attack attributed to drug trafficking groups disputing control over the border city.

The attack appeared to be intended to target a military convoy passing by, but no deaths or injuries resulted from the explosion.

The bomb may be the latest sign that drug-related violence may be about to escalate further in Monterrey, a city struggling to investigate the recent casino attack which left 52 people dead, despite a desperate shortage in trained police officers. The car bomb appears time to coincide with these circumstances that have left Monterrey vulnerable.

Milenio said the attack was the second car bomb ever deployed by Mexican cartels against the security forces, but analyst Sylvia Longmire, author of the recently published “Cartel,” counts at least four other incidents between mid 2010 and January 2011. InSight Crime counts at least another three incidents since then.

The first car bomb known to have been deployed by drug gangs was detonated in Ciudad Juarez in July 2010. The explosion killed four people, including two police officers and two medics.

The incident sparked concerns that the Mexican conflict was becoming increasingly similiar to that seen in Colombia in the early 1990s, when groups like the Medellin Cartel frequently planted bombs in public places — including goverment buildings, parks and passenger planes — that indiscriminately targeted civilians.

Even with the multiple car bombings seen since that first Juarez attack, it isn’t clear that the Mexican gangs have shifted their focus to targeting civilians rather than the security forces, which would fit more comfortably with the standard definition of terrorism. The most serious attack registered so far was an ambush, much like the one recently seen in Monterrey, aimed exclusively at the security forces. The ambush, which took place January 2011 in the central-eastern state Hidalgo, saw the detonation of a car bomb which killed a police commander and injured three other officers.

That assault was blamed on criminal gang the Zetas, the group best known in Mexico for their brutal tactics.·2011 saw imitation attacks in other states where the Zetas have a strong presence, including two car bomb attacks in Nuevo Leon in January, followed by another two attacks in Ciudad Victoria, state capital of Tamaulipas. One bombing left five people injured, the other was detonated on the 2011 Independence Day, September 16.

In many cases, the cars are packed with C-4 plastic explosives, or Tovex, a water-gel explosive, and are activated by cell phone. This is a relatively primitive way to build a car bomb, indicating that Mexican gangs still lack the sophisticated training need to build the high-power, massively destructive car bombs known as Vehicle Borne Improvised Explosive Devices (VBIED).

None of the attacks that followed have yet indicated that criminal gangs are yet capable of developing a powerful VBIED. But at this point there have been enough car bomb attacks to suggest that this method has become an accepted part of the cartels’ tactics against the security forces. The risk is that with practice and experimentation, criminal groups are growing closer to building more sophisticated vehicle bombs capable of inflicting large-scale damage.

It’s worth asking, however, if it is in the interest of Mexico’s gangs to carry out attacks which inflict indiscriminate damage on civlians. Such attacks risk courting the “terrorism” label which some U.S. congressmen are eager to make official. If we continue to see car bombs deployed across Mexico, they are likely to be more of the same: rundimentary devices whose true intention is to sow fear and panic, not inflict serious damage.