(CNN) — Russia launched its biggest wave of missile attacks on Ukrainian cities in more than a month, hours after Ukrainian President Volodymr Zelensky proposed a peace plan in front of world leaders at the G20 summit in Indonesia.

Air raid sirens sounded out across Ukraine shortly after its leader outlined a 10-point plan including the withdrawal of Russian troops and the restoration of Ukraine’s territorial integrity.

The strikes targeted power infrastructure in several regions of the country, leaving more than seven million Ukrainians without power and the supply of electricity in a critical condition, according to senior Ukrainian officials.

The deputy head of the Ukrainian Presidential Office, Kyrylo Tymoshenko, said that 15 facilities of Ukraine’s energy infrastructure had been damaged during the Russian missile strikes, but Ukrainian air defenses had shot down 70 of more than 90 missiles fired at Ukraine.

At least a dozen cities and districts were targeted, according to a CNN analysis of the missile strikes. The wave of strikes appears to be the largest since October 10, when Russia stepped up its campaign to destroy electricity, water and gas infrastructure across Ukraine.

Two missiles or rockets reportedly hit a farm in Poland near the border with Ukraine, killing two people, according to Polish media. It is unclear where the projectiles came from, but they landed roughly the same time as a Russian missile attack on western Ukraine.

Polish media showed an image of a deep impact and upturned farm vehicle at the site, near the town of Przewodow.

A government spokesman said that Prime Minister Mateusz Morawiecki has convened the Committee of the Council of Ministers for National Security and Defense Affairs.

In a video message posted to Telegram on Tuesday evening local time, Zelensky said that 85 missile strikes had been launched so far, and warned there may be more to come.

“We can see what the enemy wants, they will not succeed,” he said. “We may yet have 20 more strikes, please look after yourselves, stay in shelter for some time.”

In the capital, Kyiv, the city military administration said that one person had been killed. Two explosions had been heard, it added, instructing residents to remain in shelters. It said four missiles had been shot down.

Kyiv mayor Vitaliy Klitschko then said there had been a third strike. “Another hit in Pechersk district of Kyiv city. A high-rise building,” Klitschko said.

Power supplies were disrupted to several Ukrainian regions as a result of the missile strikes.

State power supplier Ukrenergo said the Russians were “trying to turn off the lights in the country again.”

“The attack is still ongoing, we cannot yet estimate the full extent of the damage, there are strikes on our infrastructure in all regions of the country, but the most difficult situation is in the northern and central regions,” it added.

In his video message, Zelensky said that authorities are working to restore power. “We will withstand,” he said.

In addition the country “is currently experiencing a major internet disruption,” according to Netblocks, which tracks cybersecurity and connectivity around the world, with connectivity at 67% of previous levels.

Neighboring Moldova also suffered power cuts following the Russian strikes on Ukraine, Moldovan Deputy Prime Minister and Infrastructure Minister Andrei Spinu said on Tuesday.

Spinu said in a post on his Telegram account that “following Russia’s bombardment of the Ukrainian power system,” one of the power lines carrying electricity to Moldova has been disconnected. Authorities are working to restore the connection to the line, which was not damaged but was disconnected as a safety measure, he added.

Zelensky addresses G20

Earlier on Tuesday, Zelensky set out a proposal for ending the Russian invasion, according to a transcript shared by the Embassy of Ukraine in Indonesia on Tuesday.

The president’s peace plan has 10 steps including a path to nuclear safety, food security, a Special Tribunal for Russian war crimes, and a final peace treaty with Russia, according to the speech transcript.

He urged G20 leaders to use all of their power to “make Russia abandon nuclear threats” and implement a price cap on energy imported from Moscow.

Zelensky also called on Russia to stop bombing Ukraine’s energy infrastructure as winter approaches.

“Let Russia prove by its rejection of terror that it is really interested in the restoration of peace,” he said.

Moscow has been isolated at this year’s G20 summit as multiple Western leaders vowed not to have any contact with its Foreign Minister Sergey Lavrov, who is in attendance on behalf of the Kremlin.

World leaders condemned Tuesday’s strikes. At the summit, British Foreign Secretary James Cleverly said in a tweet that the attacks targeting Ukrainian cities “shows only Putin’s weakness,” who “is losing on the battlefield and — as we saw today at the G20 — diplomatically too.”

German Foreign Minister Annalena Baerbock said “at the moment we are hearing again of brutal Russian missile attacks on Kyiv, Kharkiv and Lviv and other places, and especially again on civilian infrastructure,” during remarks on Tuesday with the International Atomic Energy Agency (IAEA) chief Rafael Grossi in Berlin.

She added that the attack “is also an unprecedented attack on nuclear safety and nuclear security.”