Authorities in Venezuela say they dismantled a drug-trafficking ring with links to a Mexican cartel after seizing more than 3.4 metric tons of cocaine.

National guard chief Gen. Nestor Reverol said Wednesday that the drugs were smuggled over the border from Colombia in bags containing rubber tires. At least five people, two of them Colombian, were arrested in raids in three states over the past two weeks.

The U.S. has been steadily stepping up pressure on high-ranking members of Venezuela's military and government officials for allegedly making the country an important transit zone for narcotics heading to the U.S. and Europe.

Reverol himself is reportedly among those being targeted. Venezuelan officials have rushed to his defense, accusing the U.S. of trying to undermine socialist rule.