Bulgaria\'s customs agency announced Thursday it had seized 53.5 kilogrammes (118 pounds) of heroin in four separate vehicles entering from Turkey. A total 99 packages of heroin weighing 51.5 kilos were found hidden in three Bulgarian cars at the southeastern Kapitan Andreevo border checkpoint late Wednesday. They were concealed at the bottom of a 30-litre container of washing detergent in each of the cars. Customs later seized two more kilos of heroin concealed in two packages of baby diapers in a Bulgarian bus also crossing the checkpoint from Turkey. The four seizures were made within a span of just two hours, the customs agency said in a statement. After a tip-off from Bulgarian officials, the Turkish customs authorities seized a possible fifth heroin load, hidden in the region of the Kapicule post on the Turkish side of the border. Officers there found a 30-litre container, identical to those seized in Bulgaria, but Bulgarian customs officials did not specify how much heroin their Turkish colleagues had found. The seizures late Wednesday were made in the presence of two Finnish observers from the EU Frontex external border control agency. Bulgaria and neighbouring Romania have been struggling to convince the EU that they can impose efficient control of the bloc\'s external border. They want to be granted admission to the Schengen free-travel area this year. But a number of EU member states remain sceptical. Bulgaria lies on the so-called Balkan drug trafficking route and about 1,000 kilogrammes of heroin are seized at its borders every year.