Mexico City (AFP) - President Andres Manuel Lopez Obrador on Sunday formally inaugurated the National Guard, a militarized police force aimed at cracking down on the country's growing crime rate and securing its borders.

Lopez Obrador said that the initial 70,000 members would be deployed to 150 regions across Mexico, and eventually 150,000 personnel will cover most of the country.

The leftist president, who took office in December 2018, had long criticized the use of soldiers in the crackdown on violent cartels.

The National Guard however is made up mainly of former soldiers and has a military leadership. Critics say its personnel are not properly trained to handle civilian tasks.

Although the force was formally inaugurated on Sunday, National Guard members have been deployed since May to hot spots across the country.

In late June, under US pressure, more than 21,000 National Guard personnel were sent to Mexico's northern and southern borders to halt Central American migrants seeking to illegally enter the United States.

Defense Secretary Luis Cresencio Sandoval said that National Guard members have been trained in police procedures, will respect human rights, and will use force in a "reasoned and proportional" manner.

Maintaining peace and security is Lopez Obrador's biggest challenge: there were a record 33,341 homicides in Mexico in 2018, the highest number of deaths since the government began tracking murders in 1997.

More than 250,000 people have been murdered since 2006, the year Mexico's military was deployed to combat the cartels. More than 40,000 people have vanished during that same time period.