Czech police are investigating nine aircraft following anonymous bomb threats targeting flights arriving at and departing from Prague Airport, with additional security measures put in place, authorities said Friday.

The threats targeted nine flights, including four arrivals and five departures, Prague Airport spokeswoman Denisa Hejtmankova said, adding that all nine aircraft were on the ground and being inspected by police, according to broadcaster CNN Prima News.

Police said in a post on US social media platform X that threats involving the alleged placement of explosive devices on board several aircraft flying to and from Prague Airport had been reported again on Friday. The airport said the security measures would not significantly affect its operations. A similar threat was reported Thursday, targeting four aircraft bound for Prague and areas of the airport. Subsequent inspections by explosives experts found no explosives or other dangerous objects. Bomb threats have also disrupted several commercial flights across Europe in recent days.