Spanish police say they have arrested two alleged gun-runners in Barcelona on suspicion they formed part of a gang involved in selling high-powered weapons to Mexican drug cartels.

A police statement says anti-tank rocket launchers, grenade launchers and sniper and assault rifles that smugglers could use to protect drug shipments from Mexico to the U.S. were among the weapons allegedly being sold. The investigation began when police uncovered evidence of money laundering and drug trafficking.

The suspects, a 40-year-old Iranian and a 44-year-old Swiss national, were arrested in November, after a surveillance operation gathered evidence of meetings with buyers in a hotel. Detailed notes of weapons ordered were seized.

Sunday's statement says the arrests took place in collaboration with the U.S. Drug Enforcement Administration.