Mexican President Andrés Manuel López Obrador has deployed Mexico's largely sidelined elite marine force to fight drug cartels, following pressure from the Trump administration to beef up its fight against illicit substances, according to the Wall Street Journal - which notes that the move marks a shift from a "counternarcotics strategy that largely ended the pursuit of high-profile arrests and focused almost exclusively on poverty alleviation."

"We are operating again," said one senior Mexican navy officer, adding "The targets we need to go after have been defined."

Marines presented Joaquín “El Chapo” Guzmán to the media in Mexico City after his capture in 2014. He later escaped, and was recaptured in 2016. (Photo: ronaldo schemidt/Agence France-Presse/Getty Images)

The new strategy comes amid growing alarm in Washington that Mexico has failed to control the drug trade - highlighted by the November murder of nine US citizens by suspected cartel hit men. According to preliminary numbers, 2019 murders in Mexico are on track to exceed 2018's record of 36,685, according to the report.

Spearheading the Trump administration's push is US Attorney General William Barr, who has visited Mexico twice to encourage AMLO to bring the marines back to counternarcotics enforcement, as well as beefing up extraditions of suspects who have fled the US while wanted for crimes. In January, Barr urged the Mexican government to target fentanyl labs, as well as crack down on seaports used to deliver precursor chemicals used in the labs.

President Andrés Manuel López Obrador of Mexico, right, met with U.S. Attorney General William Barr at the National Palace in Mexico City in December.

In exchange for the enhanced crackdown, the US has agreed to step up efforts to prevent guns from being smuggled into Mexico, according to the Journal's sources.

The marines, the Mexican security force that U.S. officials say they trust the most, were behind most high-profile arrests and killings of cartel leaders in the past two decades, including twice capturing drug lord Joaquín “El Chapo” Guzmán. The elite navy force was largely sidelined by Mr. López Obrador soon after he took office in late 2018, part of a strategy by the new government to halt the pursuit of top cartel figures and focus instead on attacking poverty—an approach it dubbed “hugs, not bullets.” Last year, the marines took part in few counternarcotics operations. But in recent weeks, marine units have been involved in a flurry of high-profile arrests, including of the head of a Mexico City cartel and close relatives of two major drug lords. -Wall Street Journal

Mexico-city based security consultant Eduardo Guerrero told the Journal that the "Hugs, not bullets" approach is changing, and that he expects Americans " to take a very proactive role in pushing Mexico to confront the most powerful groups, especially the Sinaloa and the Jalisco New Generation cartels."

The Trump administration began increasing pressure on Mexico in November following the murders of three mothers and six of their children in a fundamentalist Mormon compound in the northern state of Sonora. Cartel gunmen reportedly ambushed the families while fighting for control of the area where the victims lived.

After the massacre, Mr. Trump said the U.S. would designate Mexico’s drug cartels as foreign terrorist organizations, a move that Mexico strongly opposed. Mr. Trump suspended the decision after Mr. Barr met with senior officials during a trip to Mexico in December. -Wall Street Journal

Barr's visits have shown measurable results thus far, with Mexico stepping up the pace of extraditions (37 since December out of 58 in all of 2019) according to the Mexican Attorney General's office.