French police are searching for the pilots behind several mysterious drones that were seen cruising over Paris landmarks and secured compounds on Monday and Tuesday nights.
Unmanned aerial vehicles are already prohibited across the French capital, the Wall Street Journal reports, but the flights spotted this week have raised surveillance concerns in a city that is on high alert after the January terrorist attacks. The drones were seen flying near the Eiffel Tower, the U.S. Embassy and the Interior Ministry.
Police have not yet established how many drones were involved, or whether there was any connection between the flights.
Read next: Watch This Stunning Drone’s Eye View of Frozen Niagara Falls
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