Loulé GNR have seized around 20,000 doses of heroin found after they attempted to stop a vehicle near the railway station at 9.50pm on June 23.
Three men tried to resist arrest, with one of the men, who was detained, being shot in the pursuit.
The police gave an order for a suspicious vehicle to stop near the station but instead the driver attempted to reverse the car in order to escape according to a spokesman from the GNR.
However, the escape failed as the driver reversed into the police car with the three occupants then trying to escape by running into a wooded area, leaving behind a bag containing the 20,000 doses of heroin.
A GNR spokesman said: “One of the men was armed with a gun which he pointed towards the pursuing officers. A GNR officer fired warning shots to stop the assailants and then shot one of them in the leg.”
The arrested man has now been detained in hospital while police have launched an investigation into the identities of the other two men who escaped arrest.