Romania's defense ministry said Saturday that the country's airspace had been breached by a drone during a Russian attack on infrastructure in neighboring Ukraine.

Russians MiG-31 fighter jets equipped with hypersonic ballistic missiles completed a four-hour flight over the neutral waters of the Barents Sea as part of ongoing 'Zapad 2025' military exercises, the Interfax news agency reported on Saturday.

France said it’s deploying fighter jets to Poland and Britain announced fresh sanctions on Russia’s oil revenues and war machine Friday as European countries took steps to deter Moscow’s

The Russian surveillance and reconnaissance planes stayed in international airspace, but flew close enough to prompt NORAD to launch F-16s to intercept.

Alarms bells sounded this week in Europe after NATO jets scrambled to intercept an unprecedented Russian drone incursion in Poland. Now there is fresh unease on NATO’s eastern flank, as Russia and Belarus kick off major military drills to test the readiness of their armed forces.

Russia said on Sunday that it had used aircraft, drones, missiles and artillery to strike Ukrainian armaments factories, transport infrastructure used by the Ukrainian army, airfields and arsenals. Ukrainian officials said that Russia's largest overnight air attack of the war set the main building of the Ukrainian government in Kyiv on fire and left three people dead.

Kyiv fears that Europe will react to Russia’s drone incursion into Poland by keeping its air defenses to itself instead of helping embattled Ukraine.

In the years since Russia invaded Ukraine, NATO has focused on defending its own territory first and resisted lower-level harassment from Russia, like acts of sabotage and intimidation