The Romanian Defense Ministry on Friday said it had found possible drone fragments on an island in the Danube River, some 20 kilometers (about 12.5 miles) from the Romanian-Ukrainian border.

The discovery of such debris has previously led NATO member Romania to summon the Russian ambassador to complain about the violation of its air space.

What we know about the debris

The pieces were found late Thursday on an island on the Danube River in the Braila region, close to the border with Ukraine, the Defense Ministry said.

"Fragments that appear to have come from an aerial device [drone] were identified on a piece of agricultural land on the Big Island of Braila," the ministry said, adding that no injuries were reported. 

The ministry said it was conducting an investigation alongside other agencies, including the National Security System.

How unusual is the incident?

Romania has found drone fragments before. Pieces of a drone were found in 2023, when Moscow targeted the Ukrainian Danube ports such as Izmail, but Bucharest said it did not believe its territory was being deliberately targeted.

Russia has stepped up its missile and drone attacks on Ukraine since December. 

Last week, Warsaw demanded an explanation from Moscow after a Russian missile strayed briefly into Polish airspace. The transgression occurred amid a major missile attack on Ukraine, prompting NATO member Poland to activate F-16 fighter jets.