BUCHAREST: Romanian soldiers on Saturday found fragments of a drone "similar to those used by the Russian army" on the NATO member's territory across the border from Ukraine, the ministry of defence said.
Naval forces were combing the area of Plauru in Tulcea county based on information from local authorities of possible drone fragments.
Drone debris was already found in that area earlier this week, some kilometres away from Saturday's find.
"In the search, fragments of a drone similar to those used by the Russian army were discovered," a statement by the defence ministry said, adding the discovered elements would be picked up for analysis.
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Romanian President Klaus Iohannis said he had discussed the fresh discovery with NATO chief Jens Stoltenberg during a phone call.
"I strongly condemned this violation of our sovereign air space, which is a threat to Romanian citizens in the area," Iohannis wrote on X, formerly known as Twitter.
The Romanian military will continue search operations, the ministry of defence added.
Stoltenberg confirmed on X he had spoken to Iohannis, saying there was "no indication of intent to hit #NATO, but the strikes are destabilising. I welcome the US decision to deploy more F-16s for NATO air policing. We stand in solidarity with Romania."
The country has also beefed up "measures to strengthen monitoring and airspace security" following repeated Russian attacks across the border on Danube ports and infrastructure.
Stoltenberg said Thursday there was no sign Russia had launched a deliberate attack on alliance member Romania.
Wednesday's revelation of the first discovery of possible drone debris came after Romania repeatedly rejected claims by Kyiv that Iranian-made Russian drones fell and detonated on Romanian territory during a strike on the Ukrainian port of Izmail on Sunday night.
Since Russia's all-out invasion of Ukraine last February, NATO has been focused on preventing the war from spilling over onto its territory.