SOFIA, Bulgaria (AP) — Bulgarian authorities have seized some 436 kilograms (960 pounds) of heroin at the Black Sea port of Burgas, the district prosecutor’s office said on Monday.

The heroin was stashed in 434 packages hidden inside officially declared cargo in a trailer. The drug haul's value is estimated at 35 million euros (nearly $38 million).

The trailer had arrived at the end of July on a land route from Kyrgyzstan to the Georgian Black Sea port of Batumi, from where it crossed to Burgas.

From Bulgaria, it was supposed to continue to Alexandroupolis in Greece.

The trailer, supposedly transporting cable-laying machines, raised suspicion due to its unusually long stay at the port, anti-drug unit chief Ivan Sokolov told reporters, adding that an X-ray inspection led to the discovery of the concealed heroin.

“So far, there have been no arrests, and no persons found involved in this cross-border crime,” district prosecutor Georgi Chinev said.

A conviction on drug trafficking carries up to 20 years in prison in Bulgaria.

Bulgaria, which lies on a drug route from the Middle East to Western Europe, has taken massive steps in recent years to prevent drug trafficking.