BUCHAREST, Romania (AP) — Romania scrambled four of its fighter jets on Thursday after an unidentified object breached its airspace in the country's southeast near the Black Sea, according to the Ministry of National Defense.

The small object, likely a drone, was detected over the Black Sea moving toward the European Union and NATO member Romania at around 5 p.m. local time on Thursday by the radar surveillance system of the Romanian Armed Forces, the ministry said in a statement.

Romania, which shares a 650-kilometer (400-mile) border with Ukraine, has previously had Russian drones enter its airspace as Moscow attacks Ukrainian targets along the Black Sea and Danube River. Fragments of Russian drones have also been repeatedly found on Romanian territory near the Ukrainian border.

On Thursday, two Spanish F-18 fighter jets and two Romanian F-16s were dispatched to monitor the object, which radar signals indicated crossed into Romanian airspace near the coastal town of Eforie Nord and moved up to 14 kilometers (8.7 miles) inland.

The fighter aircraft did not spot the target, which soon disappeared from radar, according to the ministry. An investigation into a possible impact site was set to commence on Friday morning.