Ukraine’s President Volodymyr Zelenskyy has held an emergency meeting of the National Security and Defense Council of Ukraine following what Kyiv said was an attack on the Kakhovka hydroelectric power plant dam.

Earlier Tuesday, Zelenskyy said he had convened the meeting after the destruction of a part of the dam. He blamed the attack on “Russian terrorists.” Russia has denied attacking the dam, instead accusing Ukraine of undermining the structure.

Zelenskyy and other Ukrainian officials posted a video purportedly showing the dam being breached and flooding downstream.

Thousands of people living downstream of the dam have been urged to evacuate their homes amid fears of huge destruction in the southern Kherson region that’s partially occupied by Russian forces.

Andrii Yermak, the head of the Ukrainian president’s office, said on Telegram that the destruction of the Kakhovska HPP “is the biggest man-made disaster in the world in recent decades, which kills the environment and will negatively affect the lives of hundreds of thousands of people in the years to come.”

Yermak and other officials believe Russia attacked the dam in order to block Ukraine’s counteroffensive.

Russia claimed Ukraine was conducting artillery strikes on the area of the dam. CNBC was unable to verify the claims made by either side.

— Holly Ellyatt

Ukraine has begun emergency evacuations of residents in parts of the southern Kherson region after warning that the Kakhovka Hydroelectric Power Plant had been “blown up” by Russian forces Tuesday.

Ukrainian officials warned of potentially devastating flooding in the area and called on residents in 11 areas to leave.

“The water level is rising and everyone who is in the danger zone must: turn off all electrical appliances take documents and essentials take care of loved ones and pets follow the instructions of rescuers and policemen,” Ukraine’s interior ministry said.

The South command of Ukraine’s Armed Forces said on its Facebook page that the facility had been “blown up” by Russian forces and that “the scale of the destruction, the speed and volume of water, and the probable areas of flooding are being clarified.”

CNBC and NBC News have not been able to independently verify Ukraine’s claims.

Russia denied damaging the dam, claiming instead that Ukraine had undermined the structure. Vladimir Leontiev, the Russian-installed mayor of Nova Kakhovka, the city where the dam is located, said “night attacks” on the facility had “led to the destruction of the valves” and that “water from the Kakhovka reservoir began to uncontrollably be discharged downstream,” he said, Russian state news agency TASS reported.

Leontiev said there was still no need to evacuate the inhabitants of Nova Kakhovka but said “we are preparing for the worst consequences, but we hope that they will not happen.” He had initially denied there was damage to the dam.

Russia’s Ministry of Defense said on Telegram that its forces on Sunday morning fought back a large-scale Ukrainian offensive along five points in the southern direction of the annexed Ukrainian region of Donetsk, according to a Google translation.

Russia said Ukraine deployed six mechanized and two tank battalions as part of the offensive.

“The enemy’s goal was to break through our defenses on the most vulnerable, in his opinion, sector of the front,” the Russian ministry said. “The enemy did not achieve his tasks, he had no success.”

CNBC could not independently verify those claims.

The daily report of the Ukrainian General Staff only stated Monday that 29 clashes took place near the Luhansk and Donetsk regions on Sunday, according to a Google translation.

Ukraine’s Ministry of Defense published no public statements linked to the alleged attack. Kyiv’s minister of defense, Oleksii Reznikov, on Sunday posted on Twitter lyrics of Depeche Mode’s song “Enjoy the Silence,” stating “Words are very unnecessary / They can only do harm,” alongside a GIF of a soldier miming a bid for silence.

— Ruxandra Iordache

The commander of Ukraine’s ground forces on Monday said Kyiv had destroyed a Russian position near the embattled city of Bakhmut in eastern Ukraine.

“The defense forces are working. We continue moving forward,” Oleksandr Syrskyi said on Telegram, according to a Google translation.

CNBC could not independently verify developments on the ground.

Bakhmut is of both symbolic and strategic importance to Russia, providing a stepping stone for Moscow’s forces to advance into the cities of Kramatorsk and Sloviansk in the Donetsk region.

— Ruxandra Iordache

Turkey, Finland and Sweden will meet June 12 to discuss Stockholm’s bid to join the NATO military alliance, which has so far been stalled by Ankara’s objections, according to a NATO statement released Sunday.

The announcement followed a meeting of NATO Secretary-General Jens Stoltenberg and newly reelected Turkish President Recep Tayyip Erdogan in Istanbul.

Finland and Sweden renounced their long-standing policy of political neutrality following Russia’s full-scale invasion of Ukraine and jointly applied for NATO membership in June of last year. Finland was accepted and joined the military organization in April.

Stockholm’s accession has been delayed by Turkish concerns that Sweden harbors militants of the Kurdistan Workers’ Party, which Ankara, the United States, the EU and others designated as a terrorist organization.

An energy facility was set on fire following a drone attack in the Russian city of Belgorod, by the Ukrainian border, Belgorod Gov. Vyacheslav Gladkov said on Telegram overnight, according to a Google translation.

He added that services were not shut down.  

Belgorod has suffered both Ukrainian and domestic offensives in recent days. Earlier, an anti-Kremlin Russian paramilitary group, the Russian Volunteer Corps, on Sunday offered on Telegram to surrender two captive Russian soldiers to Gladkov, if the governor arrived in person to receive them in the Novaya Tavolzhanka locality.

Reuters reported that Gladkov had said he accepted the offer — but the pro-Ukraine group later said the meeting never took place, according to a Google translation.

— Ruxandra Iordache