(ANSA) - BELGRADE, APR 22 - A wave of email bomb threats has hit schools and shopping malls across the Balkans in recent days and continues today, forcing evacuations and police searches. Following early-morning emails, threats in Croatia spread from schools to large retail sites such as Rijeka's Tower Centre and ZTC. Threats were made against Montenegro's schools and the Podgorica airport, but no explosives were discovered, and police ordered daily pre-class preventive sweeps until the end of the school year. In recent days and weeks, Bosnia and Herzegovina, Slovenia, and Serbia have all received similar alerts. (ANSA).