A Russian drone hit an apartment building in Romania, the country's defence ministry said early on Friday, causing a fire and injuring two people.
The drone crashed in the eastern city of Galati as Russia carried out attacks in Ukraine near the border, the ministry said in a statement.
The Romanian General Inspectorate for Emergency Situations said the drone's entire explosive payload detonated, causing a fire on the 10th floor of the residential building.
Russian drones have strayed across the border of the Nato member country a number of times during the four-year war with Ukraine, but this was the first time citizens from Romania had been hurt. Russia has yet to comment on the incident.
"This incident represents a serious and irresponsible escalation on the part of the Russian Federation," Romania's foreign ministry said, adding Bucharest had informed the Nato secretary general and "requested measures to accelerate the transfer of anti-drone capabilities to Romania".
The emergency services said two people received medical treatment after suffering abrasions and around 70 people were evacuated as the fire was put out.
Two F-16 fighter jets were scrambled after the drones were detected in Romanian airspace, the defence ministry said.
"One of these drones entered Romanian airspace, was tracked by radar as far as the southern part of the city of Galati, and crashed onto the roof of an apartment building, with the impact triggering a fire," it said.
The River Danube nearby forms the border with Ukraine, and Ukrainian ports are regularly targets of Russian air attacks.
In an incident in April, another Russian drone caused material damage in Galati, but no injuries.
Romania's defence ministry says that since the start of the war in Ukraine, drone fragments have been found on Romanian territory on 47 separate occasions, 12 of them this year alone.
Russian President Vladimir Putin launched a full-scale invasion of Ukraine in February 2022.
Meanwhile, a nationwide air raid alert was also issued overnight in Ukraine, where officials in the south of the country said the port of Izmail in the Odesa region came under drone attack early on Friday.
And in a Russian-controlled part of Ukraine's eastern Donetsk region, three utility workers were killed in a Ukrainian drone attack on Thursday, the Kremlin-installed head of the region said.
A fourth man was seriously injured in the incident, Denis Pushilin said on the Telegram messaging app.
