Bulgarian security authorities seized 73.64 kg of heroin at Kalotina checkpoint near country's border with Serbia, officials said on Tuesday.
The drugs were found on Sunday evening in a Croatia-registered truck, transporting goods from Turkey to Bosnia and Herzegovina, the National Customs Agency (NCA) said in a press release.
After x-ray checks, the inspectors found two brown cardboard boxes with 144 packages of heroin, hidden from among the cargo, officials said.
The driver of the vehicle, a Croatian citizen, was arrested on the scene.
Since the beginning of the year, Bulgarian authorities have seized a total of 335,706 kg of heroin in 15 cases. This is the highest recorded amount for the same period since 2009