MEXICO has called for an urgent investigation into how drug cartels are using US military-grade weapons.

The Latin American country’s army is finding increasingly more belt-fed machine guns, rocket launchers and grenades from the United States.

Foreign Relations Secretary Alicia Barcena said: “The [Mexican] Defence Department has warned the United States about weapons entering Mexico that are for the exclusive use of the US army.

“It is very urgent that an investigation into this be carried out.”

In June, the Mexican army said it has seized 221 fully automatic machine guns, 56 grenade launchers and a dozen rocket launchers from drug cartels since late 2018.

Mexico has long had a problem with semi-automatic rifles permitted for civilian use in the US being smuggled into Mexico, where only low-calibre firearms are permitted and strictly regulated.

The country has launched legal action against US arms manufacturers and gun shops, arguing that they contribute to violence.

On Monday, an appeals court in Boston handed Mexico a victory in one action, reviving a $10 billion (£7.9bn) lawsuit against seven US gun manufacturers and one distributor.

Mexico argued that the companies knew weapons were being sold to traffickers and decided to cash in on the market.