Second large seizure of fentanyl at Mexico City airport

Mexican marines and customs authorities say they have seized 250 pounds (113.5 kilograms) of the synthetic opioid fentanyl at the Mexico City airport.

It was the second such large bust at the airport this month. Authorities said Tuesday the fentanyl was found in four small cardboard drums that were part of an air freight shipment.

Mexican drug cartels once favoured importing fentanyl and closely related chemical precursors from Asia through Mexico's Pacific coast seaports, but they now appear to have turned to airports.

In mid-August, customs authorities seized almost 500 pounds (220 kilograms) of a chemical used to make fentanyl at a cargo terminal at the Mexico City airport.