ATHENS — The ferries are tied up in Piraeus port and the normally frenzied streets of downtown Athens are empty of cars. The first day of May in Europe is International Workers’ Day, a holiday that traces its roots to events at Chicago but is marked by distinctly European public sector strikes, labor demonstrations, and marches.  

This May Day, from Athens to Paris by way of several points in between, the usual 24-hour period of scripted social ferment is taking a back seat to the reality of a war that, well into its second spring, is intensifying at a pace that has many leaders scrambling to keep up.

No, it was not possible in various European capitals to actually hear the latest salvo of Russian missiles hammering Ukraine, but their destructive paths loom large. Ukraine intercepted 15 of the 18 cruise missiles that were fired from Russia’s Murmansk and Caspian regions on Monday morning, but those that got through reportedly wounded at least 34 people, including five children, at the eastern city of Pavlohrad. According to some reports, the principal target was a Ukrainian ammunition depot.

The head of the Dnipro regional council, Mykola Lukashuk, said 19 apartment buildings and 25 private buildings were either damaged or destroyed in two attacks.

Missiles fired at Kyiv were successfully shot down, but the May Day barrage followed an attack on Friday in which Russia fired a mix of cruise missiles and attack drones; the missiles struck an apartment building at Uman, resulting in the deaths of 21 people, including three children. 

The rage in Ukraine is building not only in the direction of the anticipated broad spring counteroffensive but in more acts of sabotage across the border in Russia — creating new headaches for the Kremlin. At midnight on May 1, a bomb blew up a power line on the outskirts of St. Petersburg. 

On Monday morning, an explosion in the Bryansk region, which borders Ukraine, derailed the locomotive and seven wagons of a Russian freight train. No casualties were reported, but Russian authorities consistently downplay the effects of such incidents. The attacks followed a weekend in which Ukrainian drone strikes sent an oil depot in Russian-occupied Crimea up in flames. 

It was not immediately clear whether the heavy Russian shelling in the Kharkiv region was related to the uptick in reported Ukrainian counterattacks. Several homes in the city of Kupyansk, east of Kharkiv, were struck with anti-aircraft missiles.

In a bid to tamp down some of the political flames now consuming the eastern flank of Europe, Pope Francis has tossed his mitre into the ring. Aboard the papal plane on the way home from Hungary, Francis told reporters: “There’s a mission that’s not public that’s under way; when it’s public I’ll talk about it.”

He also said that the Holy See would do “all that is humanly possible” to help reunite families broken by Russia’s deportation of Ukrainian children since Vladimir Putin attacked Ukraine in February 2022.

On the ground in Ukraine, many might wish for something as benign as a labor demonstration to be taking place. It is not the case. Italian media reported that the Ukrainian army is assiduously building reinforced concrete shelters at Kherson, essentially turning the city already liberated from Russian occupiers into a fortified zone. The shelters are going up near railway stations, markets, and other public places. 

Clearly, Ukraine is girding for additional assaults on Kherson. In the meantime, the Ukrainian news agency RBC reported that Russia has set May 9 as the “deadline” for the complete occupation of the embattled eastern city of  Bakhmut. That date would coincide with Russia’s traditional Victory Day. 

On Monday Reuters reported that Ukrainian counterattacks have expelled Russian forces from some positions at Bakhmut, but the situation remains tense.

The tension is also building south of Kherson, on the perimeter of the Crimean peninsula. According to the British ministry of defense, Russia has now constructed “some of the most extensive systems of military defensive works seen anywhere in the world for many decades,” not just near the frontlines but “dug deep inside areas Russia currently controls.” 

That fortifications are also being built inside the Russian regions of Belgorod and Kursk underscores that Moscow takes the threat of a Ukrainian counteroffensive seriously. 

Yet Russia’s “particular” effort to fortify the northern border of occupied Crimea on the one hand and Ukraine’s doubling down on defenses at nearby Kherson on the other could also point the compass in the direction of a battle royale that will likely not be doused by well-intentioned messages of peace and harmony coming from Rome. 

In the meantime, something else that came from Rome is a bust: guns. The Financial Times reported that 20 self-propelled guns that Italy sent to Kyiv are unusable. The newspaper cited a Ukrainian defense official who said that “not all weapons that have been delivered to Ukraine are in good condition. None of the twenty self-propelled guns that Italy has supplied to Ukraine is functional.”

Word on the Continental street is that the tanks with which Western supporters have supplied Ukraine are in better shape, and can even withstand a bit of graffiti. On a weekend visit to Ukraine the new Czech president, Petr Pavel, wrote on one Ukrainian tank, “Russia, Go Home.”

Mr. Pavel is a former army general and served as the chairman of NATO’s military committee between 2015 and 2018. He was 6 years old when in August 1968, following a particularly ebullient spring, Soviet tanks rolled into Prague.