Seven commercial aircraft across Europe were subjected to security inspections after receiving suspected bomb threats, authorities said.
Flights in Poland, Spain, Bulgaria and Italy were among those checked for explosives following what officials described as a series of separate incidents. Airport police and on-site security teams carried out searches of the aircraft and coordinated with national law-enforcement authorities.
Officials in the affected countries said investigations are ongoing to establish the origin and credibility of the threats. Airport and airline representatives typically work closely with police and intelligence services in such cases to determine whether further action is required.
The incidents come amid heightened awareness of aviation security across the continent, and authorities urged passengers to follow directions from airport staff and security personnel. Further details were expected as inquiries progress and agencies complete their checks.