SOFIA (Reuters) - Bulgarian border police seized nearly 1,500 kilograms of cannabis discovered hidden inside a truck at a checkpoint on the Serbian border on Monday, the head of customs said.

Officials discovered the cannabis concealed among linoleum during a routine check at the Kalotina checkpoint shortly after midnight, customs agency chief Georgi Kostov told reporters.

Authorities are searching for the Serbian driver, who managed to flee into woodland near the town of Slivnitsa.

“His identity was established and a European search warrant will soon be issued,” Kostov said.

One of the biggest ever load of cannabis to be seized in Bulgaria was destined for Turkey, he said.

The driver had swapped registration numbers and documents with an accomplice at the wheel of another, empty truck in an attempt to mislead customs officers. The accomplice, who owns the vehicles, has been detained.

Bulgaria has long served as a key route for smugglers moving goods between Asia and Western Europe.