Russian President Vladimir Putin has introduced martial law in four of Ukraine's regions, parts of which are under the control of Russian troops, as Ukrainian forces continue liberating occupied territories in the country's east despite another barrage of air attacks across the country.

Putin said at an online session of the Security Council on October 19 that he signed a decree declaring martial law in Ukraine's Donetsk, Luhansk, Kherson, and Zaporizhzhya -- all of which Russia illegally annexed last month.

He didn’t immediately describe the steps that would be taken under martial law but said his order was effective starting at midnight on October 20. His decree gives law enforcement agencies three days to submit specific proposals.

The package of moves, which come nearly eight months into the war launched by the Kremlin in late February, marked the latest escalation by Putin to counter a series of defeats to Ukrainian forces since the start of September.

By extending the decree to regions beyond Ukraine, the move ensures that more Russians, already angered by a military mobilization announced last month, will more deeply feel the consequences of the war in their own lives.

Mykhaylo Podolyak, an adviser to the Ukrainian presidential office's head, called Putin's move "a pseudo-legalization of looting of Ukrainians' property."

"This does not change anything for Ukraine: We continue the liberation and deoccupation of our territories," Podolyak tweeted shortly after Putin announced martial law in the four Ukrainian regions.

U.S. President Joe Biden, speaking at the White House, said Putin is trying to get Ukraine to give up.

"I think that Vladimir Putin finds himself in an incredible difficult position and what it reflects to me is it seems his only tool available to him is to brutalize the individual citizens in Ukraine…to try to intimidate them into capitulating. They are not going to do that," Biden said.

U.S. State Department deputy spokesman Vedant Patel said earlier the declaration of martial law was a desperate tactic and any claim by Russia over the regions was "illegitimate."

Putin's move came as the Russia-installed leader of Ukraine's southern Kherson region said the evacuation has started of tens of thousands of civilians and Moscow-appointed officials in the face of a Ukrainian military advance.

Vladimir Saldo said 50,000-60,000 civilians would leave four towns on the west bank of the Dnieper River in an "organized, gradual displacement" over the next five or six days.

All of the Moscow-installed administration in the city of Kherson would evacuate, too, Saldo said.

Russian television showed footage of a number of people queuing for boats on the Dnieper River bank although it was not immediately clear how many were leaving. The forced transfer or deportation of the civilian population by an occupying power from the territory under its control is considered a war crime.

Saldo's statements came after General Sergei Surovikin, the new commander of Russian forces in Ukraine, said the situation in the southern city of Kherson is "difficult" and residents facing Ukrainian bombardment are to be evacuated.

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"The Russian Army will above all ensure the safe evacuation of the population" of Kherson, Surovikin said.

But Kyiv on October 19 accused Russia of staging a propaganda show in an attempt to "scare" the Kherson residents.

"Russians are trying to scare the people of Kherson with fake messages about the shelling of the city by our army and are also staging a propaganda show with evacuation," the Ukrainian president's chief of staff, Andriy Yermak, wrote on Telegram.

Kherson was the first big city to fall to the Russian forces in February after the start of Moscow's unprovoked invasion, but Ukrainian forces have been steadily retaking nearby territory in recent weeks.

They have pushed as far as 30 kilometers south along the Dnieper River, threatening to trap Russian troops.

Meanwhile, fresh explosions were heard in Kyiv and other areas on October 19, with a missile strike hitting a major thermal power station in the city of Burshtyn in western Ukraine.

The coal-fired Burshtyn plant in the region of Ivano-Frankivsk, which supplies electricity to three western regions and to five million consumers, was hit and on fire, according to Svytlana Onysshchuk, the regional governor. There were no casualties in the strike at the plant, which was hit by four missiles nine days earlier as well.

Serhiy Borzov, governor of the Vinnytsya region in western Ukraine, said Russia had also carried out attacks on energy facilities in his region. Russian bombardment also cut power and water in some parts of Enerhodar in the Zaporizhzhya region on October 19, said Dmytro Orlov, the mayor of the southern city located near the Zaporizhzhya nuclear power plant that's been a flashpoint of the nearly eight-month conflict.

A power plant in Kryviy Rih, a city in south-central Ukraine, was also seriously damaged by Russian shelling, leaving villages, towns, and a city district without electricity, the regional governor reported.

Russian forces also targeted Ukraine's southern Mykolayiv region again with kamikaze drones early on October 19.

The Ukrainian military's southern command said in a statement on October 19 that its forces shot down 12 drones overnight.

More than a week of air attacks has destroyed almost one-third of Ukraine's power stations and cut electricity in more than 1,000 settlements.

With Ukraine gaining momentum in the war that is now nearly eight months old, European lawmakers on October 19 recognized the country's "brave" citizens by awarding them the 2022 Sakharov Prize.

"This award is for those Ukrainians fighting on the ground. For those who have been forced to flee. For those who have lost relatives and friends. For all those who stand up and fight for what they believe in. I know that the brave people of Ukraine will not give up and neither will we," European Parliament President Roberta Metsola said in the statement.

The annual prize is named after the Soviet physicist and dissident Andrei Sakharov and was established in 1988 by the European parliament to honor individuals and organizations defending human rights and fundamental freedoms. (KB/RFE-RL)