After six weeks of intense bombardment in the besieged city of Mariupol, there are now claims that chemical weapons have been used, reports Correspondent Peter Smith
The UK has warned that "all options are on the table" if claims that Russian forces used chemical weapons in an attack on the Ukrainian city of Mariupol are proven to be true.
Soldiers were left dizzy and unable to breathe after a “poisonous substance of unknown origin” was dropped on them from a Russian drone, reported the Azov Battalion - a Ukrainian military unit.
An Azov fighter in the besieged city told ITV News they have been treating the injured and are trying to get samples out of the city to test exactly what suspected gas was used - but they currently cannot get past Russian forces.
They believe it was a chemical attack and reported seeing white smoke being released from canisters that were dropped from drones above. Soldiers have reportedly suffered fainting, respiratory problems, and blackouts.
The UK said it is "working urgently" to verify the claims but Armed Forces Minister James Heappey threatened action against Russian President Vladimir Putin if they are confirmed, warning him to "not test" Britain and its allies.
Mr Heappey told ITV News: "There's a value in being ambiguous because I don't think what you want to do is to say to Vladimir Putin the consequence of using nuclear weapons is exactly this, so he gets to make a judgement about whether or not it's worth using them.
"He has to know that the prime minister of the United Kingdom, the president of the United States, the president of France and other allies have spoken about this and that all options really are on the table.
"And if I were him, I wouldn't test us to try and test what that means."
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Britain is increasingly worried that Russia could use white phosphorus munitions in the bombardment of the city.
White phosphorous burns at extremely high temperatures and is often used to illuminate conflict zones or obscure them with smoke. It can cause horrific burns, respiratory damage, infection, shock, and organ failure, according to Human Rights Watch.
Three weeks ago, ITV News filmed Russians dropping, what some experts believed, could be white phosphorous bombs on Irpin, a town on the outskirts of the capital, Kyiv.
Other key developments:
Nearly two-thirds of all Ukrainian children, 4.8 million, have fled their homes since Russia launched its invasion of Ukraine on February 24, according to UNICEF
President Putin said he has "no doubt" Russia will "achieve our goals" in Ukraine
Fighting in eastern Ukraine "will intensify" over the next two to three weeks, as Russia continues to focus efforts in the area, says the UK Ministry of Defence
More than 10,000 civilians killed in Mariupol - but the true death toll could be double, says the city's mayor
US President Joe Biden urges India's Prime Minister Narendra Modi not to step up buying of Russian oil, as the US and other nations attempt to cut off Moscow's energy income
Officials have found "evidence of execution" and reports of mass graves in the city of Buzova after Russian troops withdrew, mounting allegations of Russian war crimes
A strike hit what is believed to be a culinary school near the airport in Kharkiv, Ukraine’s second-largest city on Tuesday, destroying the building and damaging others nearby
Ukrainian officials say a fugitive Ukrainian oligarch, who is a close associate of Russian leader Vladimir Putin, has been detained in a special operation
Meanwhile, President Volodomyr Zelenskyy announced that oligarch Viktor Medvedchuk, a close Putin ally in Ukraine, has been captured by Ukrainian law enforcement.
Medvedchuk, who is the former leader of a pro-Russian opposition party, has been detained in a special operation carried out by the country’s SBU secret service.
The fugitive was being held under house arrest before the war began over six weeks ago and disappeared shortly after fighting broke out.
It comes as President Putin said "there is no doubt that we will achieve our goals" in Ukraine and that Russia's economy has successfully resisted new Western sanctions, which he called the "blitz".
Speaking during his first known trip outside of Moscow since Russia invaded Ukraine on February 24 to the Vostochny space launch facility in Russia's Far East, President Putin said the Russian military action in Ukraine aims to "ensure Russia's own security".
President Putin, who said on Tuesday peace talks with Ukraine had hit a dead end, reaffirmed his claim that the Russian “special military operation” was aimed to protect people in areas in eastern Ukraine controlled by Moscow-backed rebels.
On Tuesday, President Putin said peace talks with Ukraine had reached a dead end
The Russian leader argued that Ukraine has been turned into an “anti-Russian bridgehead” where “sprouts of nationalism and neo-Nazism were being cultivated” - something Ukraine and its Western allies have dismissed as a cover for aggression.
Putin said “we had no other choice" but to take action and told the West that "common sense should prevail, adding: “They won’t be able to shut all the doors and windows.”
The chemical attack allegations in Mariupol came as the city's mayor, Vadym Boychenko, said corpses are now “carpeted through the streets” of the southeastern port city after Russian troops killed more than 10,000 civilians in their unsuccessful fight to capture it.
He believes the true death toll could surpass 20,000.
Mr Boychenko also gave new details of allegations by Ukrainian officials that Russian forces have been using "mobile crematoriums" in Mariupol to dispose of the corpses of victims of the attacks.
“Mobile crematoriums have arrived in the form of trucks: You open it, and there is a pipe inside and these bodies are burned,” he said.
Russian forces have taken many bodies to a huge shopping centre where there are storage facilities and fridges, the mayor added.
Mr Boychenko accused Russian forces of blocking weeks of attempted humanitarian convoys into the southeastern port city in part to conceal the devastation suffered during the six-week war, meaning information remains limited on circumstances inside the city.
A video from inside Mariupol shows rows upon rows of destroyed buildings and deserted streets covered in rubble and debris.
In another, Russian tanks brandishing "Z" on the side are seen moving close to Mariupol's harbour, while explosions and gunshots can be heard nearby.
Mariupol is expected to fall into Russian hands today, after Ukrainian forces said Monday was their "last stand" for the city.
The 36th Marine Brigade, that has been defending the southern port city for Ukraine for the past six weeks, has announced they are running out of ammunition and they are surrounded, ITV News Correspondent Peter Smith reported.
Western officials think Russia wants to bring about the fall of Mariupol to both free up troops for the fight in the Donbas region but also to create a route north for the Kremlin’s forces as they look to form a pincer movement on Ukrainian defenders in the east.
Meanwhile, the UK's Ministry of Defence (MoD) said Russian forces are continuing to withdraw from Belarus so they can redeploy troops to support operations in the east, where fighting "will intensify over the next two to three weeks as Russia continues to refocus its efforts there".
The MoD said the Kremlin's attacks remain focused on Donetsk and Luhansk, in the east, but there has been further fighting around the southern cities of Kherson, Mykolaiv and a "renewed push" towards the eastern city of Kramatorsk - where more than 50 people were killed and hundreds more wounded in a missile attack on a train station evacuating civilians last week.