Israeli security authorities busted a ring of cigarette smugglers at Ben Gurion International Airport, revealing what they called “a serious security breach.” The scheme, which came to light in recent days, involved five airport workers, who used their clearance to smuggle suitcases full of cigarettes into the country, bypassing customs and security inspections.

According to a report in Yedioth Ahronoth, the suitcases originated in Eastern Europe, where criminals would pay travelers to bring an extra suitcase on their flight without divulging the contents. Once the planes landed in Israel, the airport employees, who used their security passes to gain access to the tarmac, would transfer the suitcases to their own private vehicles, bypassing customs baggage inspections.

The scam reportedly succeeded nine times before being discovered by custom officials.

“We must seal this breach in the source countries and not wait until the contraband arrives here,” said security establishment sources. “This presents a grave threat to passengers. Things could easily escalate from criminal activity to terrorist activity.”

Yedioth reported that Israeli officials had approached their Eastern European counterparts on the matter several times in the past, but to no avail.

Last week, authorities detained a Mexican national attempting to bring three suitcases of disassembled drone parts into the country. Reports said he had enough pieces to build two sophisticated aerial drones.