An apparent booby trap or car bomb has exploded in a cartel-dominated Mexican city, wounding several officers of the country’s National Guard who approached the vehicle to inspect it.

The National Guard said on Thursday that the explosion occurred late Wednesday in the city of Celaya, in the north-central state of Guanajuato, where the Jalisco and Santa Rosa de Lima drug cartels have been fighting a bloody turf war for years.

The use of a car bomb to intentionally cause law enforcement casualties marks an escalation of the infighting between rival cartels. Some observers have drawn parallels to a 2010 car bomb blast that killed three people in the northern border city of Ciudad Juarez at the height of the 2006-2012 drug war.

The officers were reportedly responding to a report about a car parked with what appeared to be bodies inside. As they approached, the vehicle exploded, sending guard officers flying.

There was no immediate information on the condition of the wounded, though at least three suffered considerable injuries that required hospitalisation.

Mexican drug cartels have used improvised explosive devices sporadically over the last two decades. But Guanajuato security analyst David Saucedo said Wednesday’s car bomb appeared to constitute a progression into terrorist-style acts.

“These are high-impact actions that seek to create terror in the population and create massive coverage in the media and social media,” Saucedo said. “Attacks with car bombs allow gangs to cause casualties among their rivals with no risk. Making such bombs is cheap and low risk.”

Saucedo said the blast may also illustrate vulnerabilities in Mexico’s quasi-military National Guard, which was created by President Andres Manuel Lopez Obrador to act as the country’s main law enforcement agency.

He said police in Celaya – who have seen about a dozen of their colleagues murdered since the beginning of the year – tend to approach abandoned cars with much more caution, but on Wednesday, National Guard officers “fell into the trap”.

Warring drug cartels in the neighbouring state of Michoacan have used bomb-dropping drones and improvised explosive devices on roads for at least two years, and there have been suspicious blasts in Guanajuato before.

In 2022, a forensic examiner and a detective were wounded when an explosive device went off while they were examining a crime scene in Guanajuato. The device appeared to have been a booby trap, though police never confirmed that.

Wednesday’s blast came as a massive search continued for 16 state employees kidnapped at gunpoint by suspected drug gang members on Tuesday in the southern state of Chiapas.

Relatives of the abducted officers crowded onto highways and streets in Chiapas Thursday to block traffic, demanding they be found and freed.

The kidnapped officers were seen in a video posted on social media Wednesday, in which one of the victims read a statement. The statement said the abductors were demanding the resignation of at least three state police officials, including the second-in-command of the force. One of the cartels operating in Chiapas has accused the police officials of favouring a rival gang.

The Jalisco and Sinaloa cartels have launched a turf battle in the state, which borders Guatemala, for control of its drug and immigrant trafficking.

Lopez Obrador said Thursday at his morning press briefing that he was willing to investigate the state police officials whose resignation the gang had demanded – but that the gang had to release the abducted officers first.

“The first thing is for them to free the victims without any conditions,” Lopez Obrador said. “We are going to investigate the conduct of these three officials … but first, they have to release them.”

The president has steadily maintained that Mexico’s drug cartel violence problem is under control and declining.

Lopez Obrador has also taken a sort of paternalistic, non-confrontational attitude towards the cartels. On Wednesday, he warned the gang to release the kidnapped officers or “I’m going to tell on them to their fathers and grandfathers”.

On Thursday, Lopez Obrador briefly spoke about the kidnapping – and then launched into a detailed description of his breakfast menu and played a tape of his favourite new song to improve the musical tastes of young people.

The blast in Guanajuato came on the same day that authorities in the border state of Chihuahua reported that eight people had been killed and two burned-out vehicles were found following an apparent drug cartel clash in the town of Guachochi, in a mountainous region near the border with the neighbouring states of Sinaloa and Durango.

The area is known for drug cartel activity and drug production. (Al Jazeera)

•Federal forces guard the scene of an overnight car blast on June 29 in Celaya, Mexico [Stringer/Reuters]

Update news