SOFIA, March 26 (Xinhua) -- A total of 6.23 kg of heroin have been seized at Danube Bridge checkpoint near the Bulgarian town of Vidin, which borders Romania, officials said here on Monday.

The illicit drug, split into 12 packages, was found in the cavities behind the rear seat of a car attempting to leave Bulgaria, the interior ministry said in a statement.

The driver and his companion, both Bulgarians, were arrested, the statement said.

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