Here is the latest news from Russia's war in Ukraine.
1. Russia boosting production of 'powerful' weapons, says Medvedev
ADVERTISEMENTRussia is producing more destructive weapons to counter western countries that support Kyiv, said Dmitry Medvedev on Sunday.
"Our enemy is entrenched … in Europe, North America, Japan, Australia, New Zealand and a whole number of other places that have sworn allegiance to today’s Nazis," the Deputy Chairman of the Russian Security Council wrote on Telegram.
"That is why we are boosting the production of the most powerful means of destruction, including those based on new principles," he said.
Russian officials often refer to Ukraine's leadership as "Nazis", using this as a justification for their invasion. This claim that Ukraine is ruled by the far-right has been dismissed as a "plain and simple lie" by experts.
Medvedev said the weapons would be based on "new physical principles", without detailing exactly what these were.
AFP reported that this could be in reference to a new generation of hypersonic weapons that Moscow has been developing in recent years.
Such weapons fly at exceptionally high speeds, making them extremely difficult for defensive systems to intercept.
Serving as the President of Russia between 2008 and 2012, Medvedev has become one of the most vocal critics of the West within the Russian government, slamming western sanctions and alleged Russophobia.
The spectre of nuclear war has returned since Russia invaded Ukraine in February, with Russian president Vladimir Putin discussing how Russia would use nuclear weapons as a "means of defence".
Russian setbacks on the battlefield in recent months have raised fears that Moscow is considering using such weapons to reverse its fortunes.
The US State Department condemned Putin's comments, saying "any discussion, however vague, of nuclear weapons is absolutely irresponsible".
2. Freed Russian arms dealer heaps praise on Putin and Ukraine war
Viktor Bout, an infamous arms dealer dubbed the "Merchant of Death", has praised Putin, backed Moscow's assault on Ukraine and given a damning assessment of the West, during his first public interview since being released from prison.
Speaking to the Kremlin-backed RT channel, Bout said he kept a portrait of Putin in his prison cell in the United States.
"I am proud that I am a Russian person, and our president is Putin," he said. "I know that we will win."
Bout -- a former Soviet air force pilot -- was freed from the US on Friday as part of a prisoner exchange with the American basketball star Britney Griner this week.
His chequered past was the inspiration for the Nicolas Cage film Lord of War, which depicts the life of an unscrupulous weapons seller.
Since being released, Bout said he had been enjoying the snow and "air of freedom".
Bout was interviewed by Maria Butina, who herself served a short prison stint in the US for illegally acting as a foreign agent for Russia.
ADVERTISEMENTBout, 55, said he "fully" supported Russia's military offensive in Ukraine and would have volunteered to go to the front if he had the "opportunity and necessary skills".
"Why did we not do it earlier?" he said, referring to Putin's decision to launch the invasion.
Bout, who was accused of arming rebels in some of the world's bloodiest conflicts, was arrested in Thailand in a US sting operation in 2008. He was extradited to the country and sentenced in 2012 to 25 years in a maximum security prison.
He complained about the quality of food while incarcerated in the US, saying he missed the taste of garlic and strawberries.
Bout also gave a damning assessment of the western world, saying developments there looked like a suicide of civilisation.
ADVERTISEMENT"What is happening in the West is simply the suicide of civilisation. And, if this suicide is not prevented, at least within the non-Western world, within the world that is not controlled by the Anglo-Saxons, then the whole planet will commit suicide. And it may be happening in all areas, with drugs and LGBT+ among them," he said.
3. Ukraine hunts for Russian 'collaborators' in Kherson
Ukrainian authorities are rooting out Russian "collaborators" in the southern city of Kherson, AFP reports.
Kherson, which was liberated from Russian forces in November, has been placed under tight police control, with continued patrols by security personnel and tight checkpoints at the entrances and exits of the city.
“These people stayed here for more than eight months", Kherson region governor Yaroslav Yanushevich told AFP. "They worked for the Russian regime and now we have information and documents about each of them."
"Our police know everything about them and each of them will be punished,” he added.
ADVERTISEMENTKherson, a strategic port city on the Black Sea, was one of the first major cities seized by Russian troops when they rolled across the border. It had a pre-war population of nearly 300,000, though a large number of people fled to seek safety elsewhere.
Checks are made at industrial and port areas, alongside the train station, which some Kherson inhabitants still use to evacuate from the city on a daily train.
On certain roads in the city, large propaganda posters which praised Russia have been torn down and replaced with others that glorify the liberation of Kherson.
Other posters have appeared inviting residents to denounce people who they think collaborated with the Russians.
“Provide information on traitors here”, reads one of the posters, displaying a QR code linking to a website where reports can be made and a telephone number.
ADVERTISEMENT"It helps us to identify them, to know if they are on the territory that we control", said the Kherson governor.
"Most of the information is received from the local population during simple conversations ... We also analyse the accounts on social networks and continue to monitor the Internet", said Andriï Kovanyi, Head of Public Relations at Kherson's region police.
Ukrainian security services (SBU) take over the investigations, after the police.
According to Deputy Interior Minister Yevgen Yenine, more than 130 people have already been arrested for collaboration in the Kherson region.
4. Russia drones smash power network in Odesa leaving millions without power
All non-critical infrastructure in the Ukrainian port of Odesa was without power after Russia used Iranian-made drones to hit two energy facilities, officials said on Saturday.
ADVERTISEMENTThe crippling strikes are reported to have left 1.5 million people without power, in damp cold conditions.
"The situation in the Odesa region is very difficult," Zelenskyy said in his nightly video address.
"Unfortunately, the hits were critical, so it takes more than just time to restore electricity... It doesn't take hours, but a few days, unfortunately."
Since October, Moscow has been targeting Ukraine's energy infrastructure with large waves of missile and drone strikes.
Norway was sent more than 100 million euros to help restore Ukraine's energy system, Zelenskyy said, thanking the country.
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Serhiy Bratchuk, a spokesperson for Odesa's regional administration, said electricity for the city's population will be restored "in the coming days," while complete restoration of the networks may take two to three months.
Bratchuk said an earlier Facebook post by the region's administration, advising some people to consider evacuating, was being investigated by Ukraine's security services as "an element of the hybrid war" by Russia.
That post has since been deleted.
"Not a single representative of the authorities in the region made any calls for the evacuation of the inhabitants of Odesa and the region," Bratchuk said.
Odesa had more than 1 million residents before 24 February.
ADVERTISEMENT5. 10,000 Russian troops have died in Ukraine: BBC investigation
Russia's military has suffered over 10,000 confirmed deaths during its grinding invasion of Ukraine, according to research conducted by the BBC and independent Russian news outlet Mediazona.
Released on Friday, it found that 10,002 servicemen had been killed.
But the true figure is likely to be much higher than that verified by the research, the BBC added.
Scores of these casualties were elite servicemen from airborne units, plus more than 100 pilots and 430 recruits drafted by the Kremlin in October, following Russia's push to bolster troop numbers in Ukraine.
Rank-and-file soldiers suffered the greatest losses overall, with infantry units consisting of lesser-trained and inexperienced recruits making up 17% of the death toll.
ADVERTISEMENTRussia has been accused of sending newly recruited troops to the frontlines with just days of training, helping fuel a casualty figure that is already far higher than that recorded during Russia's past wars in Afghanistan and Chechnya.
Some of Russia's poorest regions have contributed a disproportionately high number of recruits to the war in Ukraine.
While soldiers from the Moscow region account for just 54 verifiable deaths in the research, the figure for the Siberian republic of Buryatia is six times higher at 356.
This far-eastern area has one-seventh of the population of the Moscow region.
Approximately 15% of Russia’s dead in the conflict are officers, including four generals and 49 colonels, the investigation found.
ADVERTISEMENTOne factor behind this is believed to be the breakdowns in communication between the Russian ranks, which forced commanding officers to travel directly to the frontlines.
In December, a senior official put Ukraine's casualty figure at 13,000.
"We are open in talking about the number of dead," said Mykhailo Podolyak, an advisor to the Ukrainian president, adding that Zelenskyy would make the official data public "when the time was right".