An officer inspects a balloon used to smuggle cigarettes into Lithuania by Belarusian smugglers, in an undated photo released by the State Border Guard Service. State Border Guard Service/AP Vilnius, Lithuania AP —

Up to 25 small hot-air balloons, some of them confirmed to be carrying smuggled cigarettes, entered Lithuanian airspace late Saturday and forced the shutdown of Vilnius Airport, delaying flights for hours, authorities said.

The balloons interfered with 30 flights, impacting some 6,000 passengers, according to Lithuania’s National Crisis Management Center. Flights resumed at 4:50 a.m. Sunday (9:50 p.m. ET, Saturday).

While the balloons turned out to be ferrying cigarettes, Europe is on high alert after intrusions into NATO’s airspace reached an unprecedented scale

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