A Russian politician says the US will be risking World War III if it has allowed Ukraine to use American-made weapons to strike Russia.

Kremlin politician Maria Butina said on Monday that the Biden administration was "trying to escalate the situation to the maximum while they still have power and are still in office".

"I have a great hope that [Donald] Trump will overcome this decision if this has been made because they are seriously risking the start of World War III, which is not in anybody's interest."

Dmitry Peskov, an official spokesman for the Kremlin, echoed those comments and said outgoing President Joe Biden was adding fuel to the fire and seeking to escalate the conflict in Ukraine.

The comments came as at least two children — a nine-year-old boy and a 14-year-old girl — were among 11 residents killed in a strike on the Ukrainian city of Sumy on Sunday, about 40 kilometres south of the Russian border, according to the regional prosecutor's office.

Six other children were injured and remain in critical condition.

Local authorities said the attack also damaged 15 buildings, including two educational facilities, and a search and rescue operation is underway, on the eve of the 1,000-day milestone of the conflict between Russia and Ukraine.

Earlier, Ukrainian President Volodymyr Zelenskyy said Russia had launched 120 missiles and 90 drones in a large-scale attack across Ukraine, including Sumy.

Russia deployed various types of drones, he said, including Iranian-made Shaheds, as well as cruise, ballistic and aircraft-launched ballistic missiles.

The attack, which targeted Ukraine's energy infrastructure, came as fears are mounting about Moscow's intentions to devastate Ukraine's power generation capacity ahead of the winter.

Ukrainian defences shot down 144 out of a total of 210 air targets, Ukraine's air force reported.

"The enemy's target was our energy infrastructure throughout Ukraine. Unfortunately there is damage to objects from hits and falling debris," Mr Zelenskyy said.

"In Mykolaiv, as a result of a drone attack, two people were killed and six others were injured, including two children."

In the southern Ukrainian city of Odesa, a separate Russian strike killed eight people and wounded 18 more, the governor of the Black Sea region said on Monday.

"According to preliminary reports, the Russian attack left eight dead and 18 wounded. One child is among the wounded. Four people are in a serious condition," the official, Oleg Kiper, wrote on social media.

Mr Kiper said earlier that the attack damaged energy infrastructure in the region, disrupted power and water supplies, and two of the victims were employees of Ukraine's state-owned power grid operator, Ukrenergo.

The combined drone and missile attack was the most powerful in three months, according to the head of Kyiv's City Military Administration, Serhii Popko.

One person was injured after the roof of a five-storey residential building caught fire in Kyiv's historic centre, according to Popko.

A thermal power plant operated by private energy company DTEK was "seriously damaged", the company said.

Zelenskyy says 'missiles will speak for themselves'

The strikes hit hours after Mr Biden reportedly authorised for the first time the use of US-supplied longer-range missiles by Ukraine to strike inside Russia, after extensive lobbying by Ukrainian officials.

The weapons would likely be used in response to North Korea's decision to send thousands of troops to support Russia in the Kursk region where Ukraine mounted a military incursion over the summer.

If confirmed, it will be the second time the US has permitted the use of Western weapons inside Russian territory within limits after permitting the use of HIMARS systems, a shorter-range weapon, to stem Russia's advance in Ukraine's Kharkiv region in May.

The first reaction from Ukraine to the long-awaited decision from the US was notably restrained.

"Today, much is being said in the media about us receiving permission for the relevant actions. But strikes are not made with words. Such things are not announced. The missiles will speak for themselves," Mr Zelenskyy said in his nightly video address.

Russian strikes have hammered Ukraine's power infrastructure since Moscow's all-out invasion of its neighbour in February 2022, prompting repeated emergency power shutdowns and nationwide rolling blackouts.

Ukrainian officials have routinely urged Western allies to bolster the country's air defences to counter assaults and allow for repairs.

Russia's Defence Ministry on Sunday acknowledged carrying out a "mass" missile and drone attack on "critical energy infrastructure" in Ukraine, but claimed all targeted facilities were tied to Kyiv's military industry.

Although Ukraine's nuclear plants were not directly impacted, several electrical substations on which they depend suffered further damage, the United Nations's nuclear energy watchdog said in a statement on Sunday.

According to the International Atomic Energy Agency, only two of Ukraine's nine operational reactors continue to generate power at full capacity.

The Russian military said on Monday it intercepted and destroyed 59 Ukrainian drones overnight over several Russian regions.

Two were downed over the Moscow region that surrounds the Russian capital, and three others over the neighbouring Tula region.

A total of 54 drones were destroyed over the Bryansk, Kursk and Belgorod regions on the border with Ukraine, according to a statement by the Russian Defence Ministry.

Moscow Mayor Sergei Sobyanin said the drones shot down outside of Moscow were heading toward the capital.

European nations react to US missiles approval

In France, politician Jean-Noel Barrot said the French government continued to consider allowing Ukraine to strike Russia with long-range missiles President Emmanuel Macron's government had provided to authorities in Kyiv.

"We openly said this was an option that we would consider if it was to allow [Ukraine] to strike a target from where Russia is currently aggressing Ukrainian territory. So nothing new on the other side," Mr Barrot told journalists ahead of a EU ministers' meeting in Brussels.

The foreign minister of NATO member Lithuania, Gabrielius Landsbergis, said he was not "opening the champagne" yet as it remained unclear exactly what restrictions had been lifted and whether Ukraine had enough of the US weapons to make a difference, while Margus Tsahkna, the foreign minister of Estonia, said easing restrictions on Ukraine was "a good thing".

"We have been saying that from the beginning — that no restrictions must be put on the military support," Mr Tsahkna said at a meeting of senior European Union diplomats in Brussels.

"And we need to understand that situation is more serious [than] it was even maybe like a couple of months ago."

Polish President Andrzej Duda said on Monday that a US decision to allow Ukraine to use US-made weapons to strike deep into Russia might be a decisive moment in the war.

"This decision was very necessary … Russia sees that Ukraine enjoys strong support and that the West's position is unyielding and determined," Mr Duda said.

He also criticised Germany for saying it would not align its policy with the US, and expressed disapproval at German Chancellor Olaf Scholz's phone call with Russian President Vladimir Putin last Friday.

"Germany may be looking for opportunities, as the German press indicates, to reach some agreement with Russia in order to return to energy contracts and to be able to buy energy resources from Russia again," Mr Duda said.

"Russia is brutally attacking Ukraine, and one of the leaders of the free world, one of the leaders of the West, a large European country, the strongest economy in Europe, is in talks with the aggressor. I absolutely believe that it was a mistake on the international political front."

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