"Debris from drones destroyed over the sea was found. Some of the drones contained explosives, while others did not," he said.
The minister said four such incidents occurred before the drone exploded in the Port of Constanța, while another likely happened afterward.
Commenting on the absence of a separate public report by the Romanian military on the explosion at the port, Mîruță said that, in peacetime, security at the Port of Constanța is not the responsibility of the armed forces.
"The Romanian Army is not responsible for guarding the Port of Constanța in peacetime. It is one of Romania's state institutions that intervenes in such situations only when asked to provide support. Under the law, other Romanian state institutions are responsible for these matters in peacetime," he said.
On June 5, a naval drone exploded in Romania's Port of Constanța. The incident occurred in the morning near berths 77 and 78, close to the headquarters of the Romanian Agency for Saving Human Lives at Sea (ARSVOM) and an oil terminal.
Romania's Defense Ministry later said the object "matched those used in the war in Ukraine" and added that the drone had self-destructed.
Ukraine's Navy said the naval drone drifted into Romanian waters after losing control due to Russian electronic warfare.
Also on June 5, Romanian President Nicușor Dan said the drone that exploded in the Port of Constanța was part of a Ukrainian military operation against Russia.