Romanian authorities have seized 333 kilograms (733 pounds) of heroin that was headed to Western Europe.

Authorities said Wednesday the drugs were found the day before stashed in two separate trucks, which each had a concealed gasoline tank. One truck was traveling toward Hungary and the other was intercepted in the northern town of Bistrita.

The drugs were sprinkled with pepper to try and avoid detection by sniffer dogs. Anti-organized crime prosecutors said two Romanian men and two Turkish men were detained.

Claudiu Cucu, a police chief, said the group had been under surveillance since 2011.

The heroin likely originated in Afghanistan and was transported through Turkey, Ukraine and Romania. The shipment's destination was the Netherlands, where it was to be distributed to other Western European countries.