A Russian drone struck an apartment building in NATO-member Romania, its defense ministry said early Friday morning, wounding two people. 

"During the night of May 28-29, the Russian Federation resumed drone attacks on civilian and infrastructure targets in Ukraine, near the river border with Romania," the 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." 

Two F-16 fighter jets were scrambled after the drones were detected in Romanian airspace, according to the ministry.  

A senior NATO military official told CBS News that NATO flew an Airborne Early Warning E-3A aircraft to increase air-domain awareness after the Russian incursion into Romania's airspace.

"NATO detected and tracked the Russian drone, but it entered Romanian airspace only minutes before striking the apartment building in Galați," the official said. "To put this in context, you are talking about something that is travelling nearly 200 km/[hour] over a populated area less than 15 km from the border. Nonetheless, we are assessing what more can be done now to optimize Romania and NATO's network of sensors and shooters to safely neutralize such threats."

Local emergency services said two people with abrasions required medical treatment, and noted that the fire was extinguished.

NATO accused Russia of reckless behavior and pledged to "defend every inch of Allied territory" after the drone crashed into the Romanian apartment building. The country's president said while domestic air defenses were bolstered, alliance partners would transfer some equipment to Romania, but he did not say what, or provide a timeline for delivery.

Russia's state-run TASS new agency cited Kremlin spokesman Dmitry Peskov as saying President Vladimir Putin was informed about the drone incident in Romania, but there was no further comment.

Drone incursions have been detected dozens of times in Romania since the start of Russia's full-scale invasion of Ukraine in 2022, but the overnight incident was the first time a residential building was hit, and the first time anyone was wounded.

Last September, Romania reported that its airspace was breached by a drone during a Russian attack on neighboring Ukraine. The country scrambled F-16s that time, too.

That same month, Poland reported that it had shot down Russian drones in its own airspace. 

NATO-member states bordering Ukraine or Russia, including Romania, Latvia, Estonia and Poland, are increasingly exposed to incursions into their territory by drones from both warring sides.

Latvia, which borders Russia, appointed a new government on Thursday, two weeks after the collapse of the previous administration due to a row over stray Ukrainian drone incursions, which have exposed vulnerabilities in the country's air defenses.

The former Latvian prime minister had accused her defense minister of not deploying anti-drone defenses fast enough to parry two wayward Ukraine attack drones, which are thought to have been knocked off course by Russian jamming.

The drones caused minimal damage but sparked widespread concern in the former Soviet republic, which is now a member of NATO and the European Union.