Mexico jumped into action on Monday in the wake of a cartel assault that freed Joaquin (El Chapo) Guzman’s son in a northern city, sending in special forces to patrol the town and asking U.S. officials to stop gun-smuggling across the shared border.

More than 400 soldiers turned up in Culiacan over the weekend after gunmen from the Sinaloa cartel briefly took control of the city and forced security forces to free the drug lord’s son from a botched arrest attempt.

“We are going to protect the citizens, that is our mission,” said Gen. Carlos Ramon Carrillo de Villar, who oversaw formations of soldiers marching at a media event. “We are fighting insecurity.”

The convoys of army trucks with mounted machine guns rumbling through Culiacan’s streets were meant to instill confidence. But a national poll on Monday showed two-thirds of respondents believe drug lords and mobsters are more powerful than the government after the gun battles last week that forced an army retreat.

President Andres Manuel Lopez Obrador has insisted the decision to release Ovidio Guzman was the only way to save lives after cartel henchmen erected roadblocks, torched trucks and opened fire with heavy, military-style weapons.

After a telephone call with U.S. President Donald Trump over the weekend, Mexican cabinet ministers met with U.S. Ambassador Christopher Landau to ask for help stemming the flow of weapons bought legally in the United States and sold to cartels south of the border.

Mexican President Andres Manuel Lopez Obrador says letting Guzman go was the right thing to do, in order to protect other lives. (Hector Vivas/Getty Images)

In a statement, Mexico said the United States had promised efforts to clamp down on the illegal trade, which is believed to be the source of most firearms in the hands of Mexican criminals.

“Arms trafficking is a significant problem and one the United States is addressing with renewed focus in Mexico,” a State Department official said in response to a question from Reuters.

Videos of the attacks in Culiacan last week showed cartel soldiers firing armour-piercing .50-calibre rifles and at least one truck mounted with a heavy machine gun — weaponry that is not available by legal means in Mexico.

Lopez Obrador has faced heavy criticism for the handling of the raid, which critics say looked like a capitulation to criminals and risked encouraging cartels to use more force to resist arrests.

The president has defended his policy of trying to dial down clashes with drug cartels to reduce murder rates.

Had security forces attempted to hold Guzman against the cartel foot soldiers, many people could have been killed, Lopez Obrador told a regular news conference.

“Not just the criminals, who are also human beings, the soldiers, who we must protect,” he said, “but [also] civilians.”

“I always have great belief in the wisdom of the people, and I know that the majority of Mexicans supported the government’s decision,” the veteran leftist said.

A forensic service employee collects bullet casings after Friday’s gun battle in Culiacan. New data shows murder rates in Mexico have dropped in September for the third consecutive month. (Alfredo Estrella/AFP/Getty Images)

Murder rate falling

Homicide data released on Sunday offered some hope for the strategy — showing murders fell in September for the third straight month.

Mexican authorities opened some 2,403 murder investigations during that month, a decline of seven per cent from the same month in 2018, and the lowest monthly total since April, according to the government figures. The months of July through September were the three most violent in 2018.

Even so, the number of murders remains on track to surpass last year’s record total of 29,000.

One poll released on Monday showed opinion was split over the operation in Culiacan. A survey by newspaper Reforma said 49 per cent disagreed with the release of the younger Guzman after his brief arrest by military police versus 45 per cent who backed it.

A separate survey by polling firm GCE said between 54 and 34 per cent were against letting him go. Both surveyed 400 people.

The GCE poll showed 63.5 per cent of respondents believed drug traffickers were more powerful than the government.

Over three-quarters in the GCE poll believed Guzman’s release would encourage gangs to continue their operations, while nearly seven out of 10 in the Reforma survey said organized crime was strengthened by what had happened.