Russian attacks on southern Ukraine are reported from the area near the Danube River, which forms the border to Romania near the Black Sea.
The military in NATO country Romania is searching for drone debris in the border area after residents reported explosions and received warning messages on their mobile phones early on Wednesday morning.
Two F16 planes have participated in search efforts near the Romanian community of Plauru, announces the Romanian Defense Department.
Drone fragments have previously been found in Romania after Russia has carried out attacks on ports in southern Ukraine.