Ukraine claims strike on Russian weapons depot

Ukrainian forces could end the Russian siege of Mariupol if supplied with heavy weapons, Ukrainian President Volodymyr Zelensky said in his video address on Monday. 

“When it comes to the necessary weapons, we still depend on the supply, on our partners. Unfortunately, we are not getting as much as we need to end this war sooner. To completely destroy the enemy on our land. And to fulfill those tasks that are obvious to each of our people. In particular, to unblock Mariupol,” Zelensky said. 

“If we got jets and enough heavy armored vehicles, the necessary artillery, we would be able to do it,” he said, “But we still have to agree on this. We still have to persuade. We still have to squeeze out the necessary decisions. I am sure that we will get almost everything we need. But not only time is being lost. The lives of Ukrainians are being lost. Lives that can no longer be returned.”

Some context: Gen. Valery Zaluzhny, commander of the Armed Forces of Ukraine, said Monday that the "defense of Mariupol continues" amid heavy fighting between Ukrainian forces inside the besieged city and Russian troops and pro-Russian separatists. 

Ukrainian officials have said around 100,000 civilians remain in the city, which has come under heavy bombardment. Ukraine's defense of Mariupol has tied down Russian units and hampered their efforts to solidify a land corridor from the Russian border to the Black Sea peninsula of Crimea.

The defense of Mariupol has also been a national rallying point for Ukrainians, and the destruction of the city has become a symbol of Russia's indiscriminate use of firepower.

On Monday, Zelensky said "tens of thousands" of people had died in Mariupol, a claim that could not be immediately verified. 

In a nightly address to the nation on Monday, Ukrainian President Volodymyr Zelensky said that Russian troops retreating from parts of northern Ukraine had deliberately left thousands of mines in their wake, in what he considered a “war crime."

In those areas, “tens if not hundreds of thousands” of unexploded ordnance had been left behind, he said, adding that teams are working to clear these “dangerous items.” 

The “invaders left mines everywhere," including in homes, on streets and in fields, he added.   

“They deliberately did everything to ensure that the return to these areas after de-occupation was as dangerous as possible. Due to the actions of the Russian army, our territory today is one of the most contaminated by mines in the world," Zelensky said.

He called these actions “war crimes” intended to “kill or maim as many of our people as possible," adding that troops would not have done so without explicit orders from Russia’s leadership. 

The United States has not confirmed the use of chemical weapons in Mariupol, but had previously warned the Ukrainians that Russia could use chemical agents in the southeastern Ukrainian city, State Department spokesperson Ned Price told CNN Monday.

“Before today, there was credible information available to us that the Russians may have been preparing to use agents, chemical agents, potentially tear gas mixed with other agents, as part of an effort to weaken, to incapacitate the Ukrainian military and civilian elements that are entrenched in Mariupol, using these agents as part of an effort to weaken those defenses,” Price said.

“We shared that information with our Ukrainian partners. We are going to be in direct conversations with them to try and determine what exactly has transpired here, and as soon as we gain additional fidelity, we’ll be in a better position to say what this was or what this may have been,” he said.

Some context: After reports emerged Monday of a possible strike involving chemical substances of some kind in Mariupol, the Ukrainian President warned the possibility should be taken seriously, though a Mariupol official said any such attack remained unconfirmed.

The UK has said it is also working with partners to investigate the reports.

CNN cannot independently verify that there has been any kind of chemical strike in Mariupol. CNN teams on the ground have so far not seen evidence of such an attack, or any imagery from Mariupol sources to verify this.

The prosecutor general of Ukraine said Monday that her office is investigating 5,800 cases of Russian war crimes, with “more and more” proceedings every day.

Speaking with CNN’s Jake Tapper on “The Lead,” Iryna Venediktova said Ukraine has identified more than 500 suspects in the sprawling probe, including Russian politicians, military personnel and propaganda agents “who wanted this war, who started this war and who continued this war.”

Her comments come as shocking atrocities in Ukraine, allegedly at the hands of Russian forces, have amplified calls to pursue war crimes charges against Russian President Vladimir Putin. After images of at least 20 bodies strewn across the street in Bucha, Ukraine, emerged earlier this month, Ukrainian President Volodymyr Zelensky called for an end to Russian “war crimes.”

Russia has denied any involvement in the incident, claiming — without evidence — that the atrocities in Bucha were staged, and part of a “planned media campaign.” But witnesses who have spoken to CNN said the carnage in the town began weeks ago, when it was occupied by Russian forces, and a video depicts Russian forces appearing to indiscriminately fire at a civilian.

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Brittney Griner, an American basketball player detained in Russia, has been able to see her representative in the country twice a week and is able to receive correspondence, ESPN reported on Monday.

Ahead of the WNBA draft on Monday, league commissioner Cathy Engelbert reaffirmed the league's commitment to bringing Griner home.

"Obviously we're in a complex geopolitical situation with Russia-Ukraine, and so this continues to be complex,” Engelbert said at a news conference Monday.

“Obviously, we're getting a ton of support from the government, from specialists. Her representation are able to visit with Brittney, we know she's safe, but we want to get her home. It's just a very complex situation right now, and we're following the advice. There's not a day that goes by that we're not talking to someone who has views on what we've been doing and how we're moving forward. I know we're all frustrated, but we do need to be patient.”

ESPN reports that the WNBA and Griner’s team, the Phoenix Mercury, are in discussions about the player and she will not be suspended this year. ESPN reports Griner will receive her full pay from the Mercury and there is a possibility the franchise will be given roster relief due to her situation.

Read more about Griner's detention in Russia:

After reports emerged Monday of a possible strike involving chemical substances of some kind in Mariupol, the Ukrainian President warned the possibility should be taken seriously, though a Mariupol official said any such attack remained unconfirmed.

In his nightly address Monday, President Volodymyr Zelensky said Russia might be preparing to escalate attacks on the besieged southeastern city.

"Today, the occupiers issued a new statement, which indicates that they are preparing a new stage of terror against Ukraine and our defenders. One of the occupiers' spokesmen said that they could use chemical weapons against the defenders of Mariupol. We take this as seriously as possible," Zelensky said.

Petro Andryushchenko, adviser to the mayor of Mariupol, posted on Telegram shortly before Zelensky’s address that information about a possible chemical attack "is not yet confirmed," adding, "details and clarifications later." 

"In any case, the announcement of the use of chemical weapons made by the occupier is not so simple," Andryushchenko said. "It is possible that the discharge of an unknown chemical is a test for the reaction in general. One scenario. But we are waiting for official information from the military."

UK investigates: Also on Monday, UK Foreign Secretary Liz Truss tweeted that she was working “urgently with partners” to investigate the reports of a possible chemical attack in Mariupol.

“Reports that Russian forces may have used chemical agents in an attack on the people of Mariupol. We are working urgently with partners to verify details. Any use of such weapons would be a callous escalation in this conflict and we will hold Putin and his regime to account," Truss wrote. 

CNN cannot independently verify that there has been any kind of chemical strike in Mariupol.  

CNN teams on the ground have so far not seen evidence of such an attack, or any imagery from Mariupol sources to verify this.

Ukrainian officials claim to have destroyed a Russian weapons depot in Novoaidar, Luhansk region.

CNN has geolocated a video and images shared to social media that appear to show the aftermath of that attack.

On Monday, Serhii Haidai, head of the Luhansk Regional Military Administration, said in a Facebook post that Ukrainian forces had destroyed a Russian "ammunition warehouse" near a Russian settlement in Luhansk.  

In a video shared by Russian state media RIA Novosti, Luhansk People’s Republic (LPR) People’s Militia officer Roman Ivanov said the Ukrainian strikes on Novoaidar destroyed “more than 20 homes, along with a warehouse filled with chemical fertilizers.”

Haidai denied Russian claims that Ukrainians targeted residential buildings.

Burned out shells and rockets are seen scattered all over the ground in the video and images, and an agricultural equipment store is spotted in the distance.