Serbian police say they have seized over a ton of marijuana and arrested six suspected traffickers.

Police said Monday that the drugs were hidden in special compartments in several fuel trucks discovered in northern Serbia.

Interior Minister Nebojsa Stefanovic hailed the bust as "impressive" and the biggest in a single police action.

Police say the haul is worth some 4 million euros ($4.3 million). They say the marijuana was packed in Kosovo and was bound for western Europe.

The western Balkans has been a key transit route for smuggling of drugs into Europe. Organized crime has flourished there since the wars of the 1990s.