At least 18 people were killed and more than 100 wounded Tuesday in a massive Russian attack on Ukrainian cities, one of the largest Kyiv has faced in the war, now deep into its fifth year.Ukraine’s air force said the assault, which began overnight and continued into the morning, included 73 missiles and 656 UAVs. It said Ukrainian air defenses intercepted or “neutralized” 40 missiles and 602 UAVs, while strikes from 30 ballistic missiles, three cruise missiles and 33 UAVs were recorded at at least 38 locations.Explosions in Kiev from Russia's massive offensive (Video: Reuters)14 View gallery Russian President Vladimir Putin ordered a massive attack on Ukraine(Photos: Sergei Bobylev, Sputnik, Kremlin Pool Photo/ AP, Gleb Garanich/Reuters)The main target was Kyiv, where authorities said four people were killed and about 65 wounded, including three children. Dozens of residential buildings were damaged, and Mayor Vitali Klitschko said one site saw the collapse of a 24-story apartment tower, with efforts underway to rescue people trapped under the rubble. At another site, a fire broke out in an eight-story building after it was apparently hit by missile debris.Eleven more people were killed and at least 36 wounded in and around Dnipro. Reports said two toddlers were among those killed there. The body of one of them, just 1 year old, was pulled from the ruins of a destroyed four-story building, along with the body of a woman. Kharkiv in eastern Ukraine was also attacked, with authorities reporting at least 14 wounded.14 View gallery Massive explosions in Kyiv from attack ordered by Russian President Vladimir Putin(Photo: Gleb Garanich/Reuters)14 View gallery (Photo: Eugene Kotenko/AFP)14 View gallery (Photo: Sergei Supinsky / AFP)14 View gallery (Photo: Roman Pilipey/ AFP)“We couldn’t understand what was happening, whether it was some kind of apocalypse,” Kyiv resident Olha Mudra said at one strike site, standing with her 6-year-old daughter Natalia near a destroyed building and damaged cars. “Everything was covered in rubble, everything was smoke, you couldn’t see anything.”As in previous massive Russian attacks, sirens sounded overnight across almost all of Ukraine, and thousands of Kyiv residents rushed to underground metro stations for shelter, some bringing pets and also mattresses to sleep on.Ukraine’s DTEK power company said the attack cut electricity to 140,000 Kyiv residents, though crews have since restored power to 110,000 of them.Russia’s Defense Ministry described the attack on Ukraine as “massive” and said it used “high-precision weapons” to target Kyiv’s defense industry. Russia repeatedly denies targeting civilians, despite attacks that have killed thousands of civilians during the war and often hit civilian infrastructure such as power stations.In recent days, Moscow threatened revenge with “systematic attacks” against Kyiv after a Ukrainian drone strike last month that Russia said hit student dormitories in occupied Luhansk province in eastern Ukraine, killing 21 people. Russia already launched a massive attack on Kyiv last Sunday in retaliation and has threatened to continue such strikes, urging foreign citizens and foreign embassy staff to “leave Kyiv now.”14 View gallery One of those injured in the attack on Kyiv (Photo: Evgeniy Maloletka/AP)14 View gallery He was injured in the Russian attack on Ukraine (Photo: Evgeniy Maloletka/AP)14 View gallery (Photo: Alina Smutko/Reuters)14 View gallery (Photo: Roman Pilipey/ AFP)14 View gallery (Photo: Roman Pilipey/ AFP)“This was a large-scale attack and an absolutely clear statement by Russia: If Ukraine is not protected from ballistic missile and other missile strikes, these attacks will continue. Europe needs its own anti-ballistic defense so that this war can finally be brought to an end. And U.S. assistance in supplying interceptors for Patriot systems is absolutely necessary. We are counting on the support of our partners and on effective responses to today’s attack.”The attacks on Ukrainian cities come as Kyiv also continues launching drone strikes deep inside Russia, in an effort to disrupt Russia’s oil industry and undermine President Vladimir Putin’s standing among the Russian public.Russia said Tuesday morning that its air defenses intercepted 148 Ukrainian drones overnight. In the southern Krasnodar region, authorities reported a drone strike on the Ilsky oil refinery. They said the facility caught fire after the strike, and Ukraine’s military later confirmed that it had attacked the site. In Belgorod region, which borders Ukraine, local authorities said an 11-year-old boy was wounded when a Ukrainian drone hit a home.14 View gallery Crowds of Ukrainians took shelter underground in the Kiev metro (Photo: Alina Smutko/Reuters)14 View gallery (Photo: Tetiana Dzhafarova/AFP)14 View gallery (Photo: Alina Smutko/Reuters)The escalation in recent weeks, alongside U.S. Secretary of State Marco Rubio’s statement that Washington is effectively freezing its mediation efforts for a ceasefire between the sides, has raised concern in Europe about a possible spillover of the fighting into nearby NATO countries.On Tuesday morning, Poland’s military said it scrambled fighter jets to secure the country’s airspace and prevent Russian drones launched toward Ukraine from entering Poland. In recent months, there have already been several cases of drones entering countries near Russia and Ukraine. OnFriday, a Russian drone hit an apartment building in the Romanian town of Galați, near the Ukrainian border, wounding two people.Europe reacted angrily to that incursion, which comes amid suspicions that Russia is now testing NATO members’ commitment to defend one another against a future Russian attack on one of them.“Russia’s war of aggression has crossed another line,” European Commission President Ursula von der Leyen said over the weekend. “As we continue to strengthen our security and deterrence, especially on our eastern border, we will continue increasing pressure on Russia.”Europe fears Putin, amid his failure to subdue Kyiv after more than four years of war and increasingly frequent Ukrainian attacks deep inside Russia, may try to “reshuffle the deck” by expanding the conflict beyond Ukraine’s borders.14 View gallery The building hit in Romania last weekend by a Russian drone (Photo: Romanian Department for Emergency Situations (DSU)/Handout via Reuters)The Wall Street Journal reported last week that, while European security officials do not currently see immediate signs that Moscow is moving troops or equipment ahead of an attack on the Baltics or other NATO territory, the concern is that attrition in Ukraine could push Moscow toward escalation.According to Western intelligence assessments cited in the report, Russia is losing nearly 35,000 soldiers a month — more than its recruitment rate — meaning that continuing the war at the current pace could become impossible without another forced mobilization. Kaja Kallas, the European Union’s foreign policy chief, warned that at such a stage the Kremlin may need escalation to justify such a move domestically.Meanwhile, the Financial Times reported Tuesday morning that the U.S. is discussing with its European allies the deployment of additional nuclear weapons on the continent, as part of an effort to ease their concerns about a weakening U.S. commitment to their defense.According to the British newspaper, the U.S. administration hopes to calm those fears and stress that the nuclear umbrella will not be affected by the reduction of American forces, even as responsibility for conventional defense increasingly shifts to the Europeans themselves.Three people familiar with the details told the Financial Times that in discussions between the U.S. administration and NATO allies, American representatives signaled a “willingness” to deploy nuclear weapons in additional European countries, beyond the six where such weapons are currently stationed under Washington’s sole control: Belgium, Germany, Italy, the Netherlands, Turkey and Britain.The officials said several countries on NATO’s eastern flank, including Poland and some Baltic states, have expressed interest in hosting U.S. nuclear weapons, but stressed that no decision on the matter is expected soon.NATO Secretary General Mark Rutte said last month that allies share “a common understanding that while the U.S. will shift more attention and resources to other theaters, overall deterrence and defense in Europe must remain intact.”He issued an explicit warning to Russia: “If anyone is stupid enough to attack us, the response will be devastating.”