Russia fired missiles at targets across Ukraine on Tuesday, hitting at least four cities including Kyiv, the capital, as Moscow unleashed its broadest aerial attack since it retreated from a key city in the south.

Missiles hit at least two residential buildings in the centre of Kyiv, and struck the country’s second-largest city, Kharkiv, in the northeast. Explosions were also reported in Lviv, in western Ukraine, as well as in the city of Khmelnytskyi in the centre of the country, regional and city officials said on the Telegram social messaging app.

Andriy Yermak, an adviser to President Volodymyr Zelensky of Ukraine, said that Russia timed its attack for the G20 meeting of world leaders in Bali.

“Does anyone seriously think that the Kremlin really wants peace?” he wrote on Twitter. “It wants obedience. But at the end of the day, terrorists always lose.”

The Ukrainian Air Force warned earlier this week that Moscow was stockpiling missiles to renew its assault on Ukraine’s already battered energy infrastructure. On October 10, Russian forces launched a devastating series of attacks, including with drones, that targeted more than 10 cities, including Kyiv. The attacks struck civilian targets and infrastructure.

The explosions from Tuesday’s strikes sent plumes of smoke rising above the capital. Medics were racing to Kyiv’s Pechersk district, a wealthy area that is home to many embassies. At least four missiles were also shot down over the capital, city officials said.

Since October 10, Russia has launched missiles against Ukraine’s energy infrastructure, causing damage at a time when businesses and homes are particularly vulnerable as winter approaches. Those attacks, which continued for weeks, were in retaliation for an explosion at the bridge linking the Crimean Peninsula and Russia that Moscow blamed on Ukraine. There was evidence that power and water facilities were again a target on Tuesday.

The mayor of Kharkiv, Igor Terekhov, said that city workers were trying to restore power supplies following the attack, while Serhiy Gamaliiof the military administration in Khmelnytskyi, said electrical service had been knocked out there, too.

In the past, Russia has appeared to launch missile strikes at Ukraine at a time of particular international focus on the country. In July, it hit the port city of Odesa a day after Moscow signed an agreement that enabled Ukraine to start exporting its grain via the Black Sea.

The barrage of strikes came as air raid alerts were issued across Ukraine.

They followed what have been days of euphoria in Ukraine after one of its biggest military successes so far of the nearly nine-month Russian invasion — the retaking last week of the southern city of Kherson.

New York Times News Service and Reuters