Ukraine's military said on Monday that Russia attacked the Kyiv region with eight ballistic missiles, prompting concerns that Russian forces have begun targeting the country's infrastructure as winter takes hold.

The Ukrainian air force said it shot down the missiles. But the mayor of Kyiv said four people were wounded by falling debris.

The military also said Russia launched 19 cruise missiles from strategic bombers last Friday.

The British defense ministry on Sunday tweeted that Russia conducted a major wave of strikes using its heavy bomber fleet.

The ministry said the missiles were highly likely Russia's premier air-launched cruise missiles. It added that Russia has almost certainly been stockpiling these missiles for use in the winter campaign.

It went on to say, "This was probably the start of a more concerted campaign by Russia aimed at degrading Ukraine's energy infrastructure."

Meanwhile, Ukrainian President Volodymyr Zelenskyy is visiting Argentina to attend the swearing-in ceremony of the country's new president, Javier Milei.

Zelenskyy appears set to strengthen ties with emerging and developing nations, known as the Global South, through his meetings with leaders of Latin America.

Ukraine's presidential office said Zelenskyy will start a working visit to the United States on Monday for talks with US President Joe Biden in Washington.

The office said discussions in Washington will include joint projects on the production of weapons and air defense systems.