Two NATO members said Sunday that Russian drones violated their airspace, one reportedly flying into Romania during nighttime attacks on neighboring Ukraine and another crashing in eastern Latvia the previous day.

A drone entered Romanian territory early Sunday as Moscow struck “civilian targets and port infrastructure” across the Danube in Ukraine, Romania’s Ministry of National Defense reported. It added that Bucharest had deployed F-16 warplanes to monitor its airspace and issued text alerts to residents of two eastern regions.

It also said investigations were underway of a potential “impact zone” in an uninhabited area along the Romanian-Ukrainian border. There were no immediate reports of casualties or damage.

Later on Sunday, Latvia’s Defense Minister Andris Sprūds said a Russian drone fell the day before near the town of Rezekne, and had likely strayed into Latvia from neighboring Belarus.

Rezekne, home to over 25,000 people, lies some 34 miles west of Russia and around 47 miles from Belarus, the Kremlin’s close and dependent ally.

While the incursion into Latvian airspace appeared to be a rare incident, Romania has confirmed drone fragments on its territory on several occasions since Russia invaded Ukraine in February 2022, as recently as July this year.

Mircea Geoană, NATO’s outgoing deputy secretary-general and Romania’s former top diplomat, said Sunday morning that the military alliance condemned Russia’s violation of Romanian airspace. “While we have no information indicating an intentional attack by Russia against Allies, these acts are irresponsible and potentially dangerous,” he wrote on a post on X.

Latvia’s military on Sunday similarly said there were no indications that Moscow or Minsk purposely sent a drone into the country. In a public statement, the military said it had identified the crash site, and that a probe was ongoing.

The Latvian defense minister sought to downplay the significance of the drone incursion.

“I can confirm that there are no victims here and also no property is infringed in any way,” Mr. Sprūds told the Latvian Radio on Sunday, adding that any risks in the event were immediately eliminated: “Of course, it is a serious incident, as it is once again a reminder of what kind of neighboring countries we live next to.”

Ukraine Foreign Minister Andrii Sybiha called the incursions “a reminder (that) the aggressive actions of the Russian Federation go beyond Ukraine’s borders.”

“The collective response of the Allies should be maximum support for Ukraine now, to put an end to (Russian aggression), protect lives and preserve peace in Europe,” Mr. Sybiha said in a post on X.