A new round of missile attacks struck the southern Ukrainian city of Zaporizhzhia Tuesday, as the death toll from the previous day’s widespread Russian missile barrage across Ukraine rose to 19.

Missiles struck a school, a medical facility, and residential buildings in Zaporizhzhia, the city council secretary, Anatoliy Kurtev, said. The State Emergency Service said 12 S-300 missiles slammed into public facilities, setting off a large fire in the area. One person was killed.

The S-300 was originally designed as a long-range surface-to-air missile. Russia has increasingly resorted to using repurposed versions of the weapon to strike targets on the ground.

The morning’s air-raid warnings extended throughout the country, sending some residents back into shelters after months of relative calm in the capital and many other cities. That earlier lull had led many Ukrainians to ignore the regular sirens, but Monday’s attacks gave them new urgency.

Beside the usual sirens, residents in the capital, Kyiv, were jolted early Tuesday by a new type of loud alarm that blared automatically from mobile phones. The caustic-sounding alert was accompanied by a text warning of the possibility of missile strikes.

The state emergencies service said 19 people died and 105 people were wounded in Monday’s missile strikes that targeted critical infrastructure facilities in Kyiv and 12 other regions. More than 300 cities and towns were without power, from the Ukrainian capital all the way to Lviv on the border with Poland. Many of the attacks occurred far from the war’s front lines.

With Ukrainian forces growing increasingly bold following a series of battlefield successes, a cornered Kremlin is ratcheting up Cold War-era rhetoric and fanning concerns it could broaden the war and draw in more combatants. As a measure of growing international concern, a hastily convened virtual gathering of G7 leaders will take place today.

Russia’s deputy foreign minister, Sergei Ryabkov, warned Tuesday that Western military assistance to Kyiv — including training Ukrainian soldiers in NATO countries and feeding Ukraine real-time satellite data to target Russian forces — has “increasingly drawn Western nations into the conflict on the part of the Kyiv regime.”

Mr. Ryabkov said in remarks carried by the state RIA-Novosti news agency that “Russia will be forced to take relevant countermeasures, including asymmetrical ones.” He said that though Russia isn’t “interested in a direct clash” with the U.S. and NATO, “we hope that Washington and other Western capitals are aware of the danger of an uncontrollable escalation.”

Some voices in Washington seem to think that a dramatic attack on a strategic bridge in Russian-occupied Crimea over the weekend did not necessarily precipitate the new barrage of missile strikes. Speaking to CNN,  the coordinator for strategic communications at the National Security Council, John Kirby, said, “It likely was something that they had been planning for quite some time. Now that’s not to say that the explosion on the Crimea bridge might have accelerated some of their planning.”

Russian nationalist commentators and the state media’s war correspondents lauded Monday’s attacks as an appropriate, and long-awaited, response to Ukraine’s successful counteroffensive in the northeast and the south and a weekend attack on the key bridge between Russia and Crimea, the prized Black Sea peninsula Russia annexed in 2014. The full extent of the damage across Ukraine caused by Moscow’s revenge strikes is emerging even as the country girds for more. Overall morale is undiminished, but according to one European newspaper, Italy’s La Repubblica, Russia’s brutal reprisal attacks have even prompted some in Ukraine to reproach their own government for attacking the bridge in the first place.

In any case, Russia  almost certainly has more retaliation in store. On social media a former Russian president, Dmitry Medvedev, wrote that Ukraine “will always pose a lasting, direct and immediate threat to Russia,” adding: “That’s why along with protecting our people and securing our country’s border, our future actions, in my opinion, should aim to fully dismantle the Ukrainian political regime.” 

Ukraine also has more weapons coming with which to fight back. Last week Washington announced a $625 million military aid package for Ukraine’s army, with a pledge to ship four more Himars precision rocket launchers, 32 artillery pieces, 75,000 artillery rounds, and 200,000 rounds of small arms ammunition. After Monday’s attacks and a fresh appeal from President Zelensky, President Biden has indicated that he will supply Kyiv with advanced air defense systems.

According to a statement from the British government, the British prime minister, Liz Truss, is expected to say during today’s virtual G7 gathering, “Nobody wants peace more than Ukraine. And for our part, we must not waver one iota in our resolve to help them win it.”