Bulgarian authorities said they seized 353 million euros ($441.60 million) worth of hashish on Thursday, their biggest drugs find in 15 years, in a consignment bound for Belgium and the Nertherlands.

The 11,756 kg of hashish came from Morocco and was hidden in a storage unit in the village of Mirovyane near the capital Sofia, the interior ministry said.

Bulgaria, eager to prove it is fit to join the European Union's Schengen zone of borderless travel and able to curb rampant organised crime and corruption, is a key transit route for drugs smuggled to Europe.

On Monday the Balkan country seized 4,200 kg of hashish in a truck that authorities said was on its way to Belgium. ($1 = 0.7994 euros)