SOFIA, Dec. 18 (Xinhua) -- Bulgarian law enforcement authorities have seized 10.345 kg of heroin at the country's Kapitan Andreevo checkpoint near the border with Turkey, officials said Tuesday.

The drug, split into 20 packets, was found early on Monday morning in the spare tire of a car entering from Turkey, the Prosecutor's Office said in a statement on its website.

Authorities estimated that the value of the heroin on the black market would exceed 540,000 U.S. dollars.

The driver of the vehicle, a 45-year-old Serbian citizen, was arrested at the scene, the statement said, adding that the investigation is ongoing.

Bulgaria, a key transit route for drugs smuggled from Asia to Europe, seized 602.6 kg of heroin at its borders in 2017.