MILAN (AP) — Flights from across Europe were diverted or forced to make emergency landings on Thursday because of bomb threats, authorities said. So far inspections have not turned up hazardous or suspicious materials.

The incidents followed hoax bomb threats earlier this week that prompted searches, diversions and, in one case, a military escort.

More than a dozen flights were targeted, included those from Copenhagen, Dublin, Helsinki, Madrid, Milan and Warsaw.

Such threats aren’t a new phenomenon but come at a time of increased geopolitical tensions and signs of “disruption,” like attacks on supermarket refrigeration systems, drone incursions in Europe and mysterious triggers to alert apps.

The latest on Thursday's developments:

An Aer Lingus plane rerouted to western France while en route from Dublin to Rome is standing on the tarmac at a military air base in Evreux, under an overcast sky.

A Red Cross vehicle is nearby but no activity is visible at the base of the plane. Metal gates ring the base and outsiders are not allowed in.

It is unclear where the passengers and crew are being held while explosives experts examine the plane.

Finnair said that two of its flights, AY1761 from Helsinki to Rome and AY1471 from Helsinki to Vienna, faced unfounded or hoax bomb threats Thursday.

“Both flights landed safely at their destinations, and customers have disembarked the aircraft,” it said.

Nothing suspicious were found on the planes, it added. The plane to Rome was inspected and will depart back to Helsinki, while the flight to Vienna will “return to traffic normally after inspection.”

In the Czech Republic, police were sent to Prague’s Vaclav Havel Airport to prepare for the landing of four planes after receiving threats of explosive devices on board. Police said that “all necessary security measures have been activated.”

Police later said searches of the planes that landed in Prague found nothing suspicious. They did not give details on where the flights originated from.