Earlier in the day, the Romanian Defense Ministry said that fragments of a drone "similar to those used by the Russian army" were discovered some 2.5 kilometers (1.5 miles) southeast of the border village of Plauru, marking the second such incident in a week. On Wednesday, debris from a possible drone was found close to Romania's border with Ukraine, but NATO said it had no information indicating any intentional attack by Russia.
"Spoke to [Romanian President Klaus Iohannis about] Russian attacks on Ukraine by the Danube [and] drone parts found in Romania. No indication of intent to hit NATO, but the strikes are destabilizing," Stoltenberg wrote on X, formerly known as Twitter.
The NATO chief added that he welcomed the US decision to deploy more F-16 jets to increase air policing.
Iohannis, in turn, said on social media that he "strongly condemned" the latest violation of his country's airspace, describing it as a "threat to Romanian citizens in the area."
An air raid alert went off on Monday night in Ukraine's Odesa region. The Ukrainian Foreign Ministry alleged that Russian drones fell and detonated in Romanian territory. The Romanian Defense Ministry rejected the allegation, saying that the Russian military never posed direct threats to Romania's territory or territorial waters.