President Vladimir Putin has blasted the West for trying to "tear apart" Russia and said in an interview aired on national television that his offensive in Ukraine aimed to "unite the Russian people".
About 100 kilometres from the Ukrainian border, Russian air defence troops shot down a Ukrainian drone early on Monday as it approached a Russian airbase, with the debris killing three, news agencies reported.
"As a result of the fall of the wreckage of the drone, three Russian technical servicemen who were at the [Engels military] airfield were fatally injured," the defence ministry announced, according to the TASS news agency.
Monday will also see a call from Ukraine for Russia to lose its veto-wielding permanent seat on the powerful UN Security Council, said Kyiv's Foreign Minister Dmytro Kuleba.
It comes a day after Putin accused his country's "geopolitical opponents [of] aiming to tear apart Russia, the historical Russia".
Putin has used the concept of "historical Russia" to argue that Ukrainians and Russians are one people – undermining Kyiv's sovereignty and justifying his 10-month invasion of Ukraine.
"Divide and conquer, that's what they have always sought to accomplish and are still seeking to do," Putin said in an interview.
"But our goal is different: it's to unite the Russian people."
Putin declared his government was acting "in the right direction… protecting our national interests, the interests of our citizens, of our people".
He repeated that Moscow was ready to negotiate and appeared unfazed when asked about the new air defence system the United States will deliver to Ukraine.
"Of course we will destroy it, 100 percent!" Putin said, referring to the Patriot missile battery promised to Ukrainian President Volodymyr Zelensky.
In televised remarks on Sunday night, Ukraine's Kuleba said Russia had lost its claim to a permanent Security Council seat.
"We have a very simple question: Does Russia have the right to remain a permanent member of the UN Security Council and to be in the United Nations at all?" he said.
"We have a convincing and reasoned answer – no, it does not," he continued, adding that the issue had been raised in diplomatic circles at the "lower level".
The powerful 15-seat Security Council has five permanent members – Russia, the United States, Britain, France and China – who carry veto power that can block any resolution.
Zelensky last week earned firm pledges of support from Biden during his first trip out of Ukraine since the conflict began – including the Pentagon's most advanced air defence system.
Western military and financial aid has been crucial for Ukraine's pushback of Russian troops – including from Kherson, the only regional capital that was held by Russia.
Despite Russia's retreat from the city, it remains within reach of Moscow's weaponry and under constant threat.
The Ukrainian army counted 71 strikes on the partly recaptured Kherson region on Saturday, including 41 on the city.
This included deadly shelling on a busy market in the city centre that left 10 people dead and 55 wounded.
The Russian-installed head of the Kherson region, Vladimir Saldo, said on Telegram the shelling was "a disgusting provocation" by Ukraine used to blame Russia.
In his daily address on Sunday, Zelensky condemned Russian "terrorists" and thanked all his compatriots – including soldiers, doctors and volunteers – involved in defending Ukraine.
"Thank you... to everyone who came to Kherson to help. To save the wounded from the terrorists' strike on Christmas," Zelensky said.
On Sunday, church bells pealed throughout Kyiv as Orthodox Christians attended Christmas services, in a break with the Russian spiritual leaders who will mark the holiday in two weeks.
At a service in central Kyiv, worshipper Olga Stanko told AFP she supported any move that would distance Ukraine from Russia.
"The war has brought us so much grief," she said. "We cannot do this with Russia, remain under its influence."
The decision by some Ukrainian churches to observe Christmas on 25 December highlights the deepening rift between religious leaders in Kyiv and Moscow.
An Interfax-Ukraine news agency poll showed an increasing number in favour of moving the Christian holy day to 25 December, jumping from 26 percent in 2021 to 44 percent in 2022, though 31 percent were still against it.
Ukraine had been under Moscow's spiritual leadership since at least the 17th century, but part of the Ukrainian Orthodox Church broke with Moscow in 2019 over Russia's annexation of Crimea and support for separatists in the east.
In May, the Russia-backed branch of Ukraine's Orthodox Church also severed ties with Moscow.
From St Peter's Basilica at the Vatican, Pope Francis called for an end to the conflict.
"May the Lord… enlighten the minds of those who have the power to silence the thunder of weapons and put an immediate end to this senseless war!" the Argentine pontiff said.