LVIV, Ukraine — Although the message was likely intended for NATO member countries, Lviv’s residents heard the Russian memo loud and clear in the wee hours of Sunday morning.

The thuds of a Russian missile barrage outside the city awakened many in Lviv several hours before sunrise and prompted intermittent air raid sirens throughout the morning.

An estimated eight Russian missiles struck the Center for International Peacekeeping and Security, about an hour’s drive northwest of Lviv and just 15 miles from the Ukrainian-Polish border.

The site has hosted joint drills with NATO personnel in the past, though in a telephone call a Ukrainian military spokesman said no foreigners were killed or injured in this morning’s strike.

In a tweet, the Ukrainian minister of defense, Oleksii Reznikov, attributed the attack to Russia and explained that foreign military instructors work at the location, adding that “information about the victims is being clarified.”

At least 35 people were killed in the morning strike, and another 134 sustained injuries.

Mr. Reznikov added that the strike represents a “new terrorist attack” on Europe’s future peace and security and urged Western countries to respond by imposing a no-fly zone over Ukraine.

In a separate strike, missiles struck a regional airport hub at Ivano-Frankivsk, a town of about 240,000 residents 80 miles southeast of Lviv. It was unclear how much damage the airport sustained or if there were any casualties.

The attacks represent a significant Russian escalation of the war in Ukraine and represent its westernmost strikes.

Just yesterday, Russia announced that it would consider arms shipments to Ukraine from NATO member countries to be legitimate military targets, possibly foreshadowing today’s strikes and threatening the lifeblood of Ukrainian resistance against the Russian invasion.

Anti-tank and anti-aircraft weapons from America and other NATO members have proved invaluable to the beleaguered Ukrainian defenders, who are outmanned and outgunned by Russia’s invasion force.

Although concrete figures are difficult to verify independently, American and Ukrainian officials agree that Russian equipment losses are significant and potentially unsustainable. Scenes from social media are rife with destroyed or abandoned Russian military vehicles.

Lviv’s proximity to Poland has transformed the regional capital into an important military and humanitarian hub. Weapon shipments from the west head to Lviv for onward distribution, and refugees fleeing war-torn east Ukraine stop in the city en route to Poland and Germany.

Despite the proximity of today’s strikes, a feeling of calm is palpable among Lviv’s population. If anything, the dual strikes seem to have stiffened the resolve of the city’s residents, helping to stave off any sense of panic.

Interviews with several Ukrainians in Lviv showed that the Russian strike had persuaded few to leave the country. However, it is clear that the relative peace and stability enjoyed in the country’s western areas may soon be drawing to a close.