Kherson dam: Importance of 'catastrophic' destruction in Ukraine explained

Watch: Russia blows up major dam in Kherson region, says Ukraine

A large dam in an area of Ukraine controlled by Russia has been destroyed forcing thousands to flee their homes and creating the "largest man-made environmental disaster in Europe in decades."

Ukraine's military accused Russia of blowing up the Nova Kakhovka dam in the Kherson region.

Drone footage released on Tuesday and tweeted by Zelensky appears to show water gushing from the breached dam.

He accused "Russian terrorists" of destroying the dam but Russia has blamed Ukraine for the attack.

People are being evacuated from nearby communities with several villages already flooded, while there are concerns about the impact on a nuclear power station about 100 miles upstream, which uses the reservoir behind the dam for cooling water.

Mykhailo Podolyak, a senior aide to Zelensky, told CNN of the dam's destruction: "The consequences are already catastrophic."

Yahoo News UK explains the importance of the dam's destruction:

What happened?

According to Ukraine, Russia blew up the dam at the Kakhovka Hydroelectric Power Plant in the city of Nova Kakhovka.

Ukrainian officials have accused Russia of detonating the dam from inside the engine room.

The dam's destruction could hinder the Ukrainian counteroffensive, which began on Monday.

Footage on social media circulated on Tuesday showed a large breach in the dam and water flooding downstream in the direction of the city of Kherson, less than 50 miles away.

Oleksandr Prokudin, the head of the Kherson region, told Ukrainian television that residents are being evacuated by bus and train, adding that 16,000 people were in a "critical zone".

Ukraine said more than 80 villages have been flooded.

Ukraine’s president, Volodymyr Zelensky, declared the destruction of the dam as an act of terrorism and the "largest man-made environmental disaster in Europe in decades".

• Ukrainian dam destroyed in blow to counter-offensive (The Telegraph, 4 min)

Why is the dam so important?

The dam is in the Kherson region of Ukraine, which is currently split between Russian and Ukrainian control.

It was built in the Soviet era and is one of six dams along the Dnipro River.

The dam is of huge strategic significance, as Russia may have believed Ukrainian troops would use the road over it to cross the river into the area it now controls.

The dam holds back a massive reservoir of water that supplies a number of communities upstream.

Russia has carried out previous attacks on dams since its invasion of Ukraine began, causing flooding and disruption to power supplies.

Although the dam lies within Russian-controlled territory, the main communities now at risk of flooding are in Ukrainian-governed lands.

Kherson is a strategically important region in the war as it has the only land link to the Crimean peninsula.

Russia controls the larger part of the region to the south and east of the Dnipro.

On the other side of the bank Ukraine controls the rest of the oblast, including the city of Kherson which is under threat of flooding.

"I was evacuated from the flooded village of Antonivka. Our local school and stadium downtown were flooded... The road was completely flooded, our bus got stuck," Lidia Zubova, 67, told Reuters as she waited for a train to evacuate people from Kherson.

• What is the Kakhovka dam in Ukraine and why is it important? (Reuters, 3 min)

What has been said?

Zelensky said the dam attack was the work of "Russian terrorists".

He wrote on Twitter: "The destruction of the Kakhovka Hydroelectric Power Plant dam only confirms for the whole world that they must be expelled from every corner of Ukrainian land.

"The terrorists will not be able to stop Ukraine with water, missiles or anything else."

Charles Michel, the president of the European Council, blamed Russia for the attack and called it a "war crime".

He tweeted that he was "shocked by the unprecedented attack of the Nova Kakhovka dam".

He added: "The destruction of civilian infrastructure clearly qualifies as a war crime - and we will hold Russia and its proxies accountable."

Prokudin, the head of the Kherson region, said Russia had committed "yet another act of terror".

He warned that water levels in the Dnipro River will be "critical" within five hours.

The United Nations Office for the Coordination of Humanitarian Affairs (OCHA) said: "The destruction of the Kakhovka dam puts thousands of civilians in danger, leaving many with no homes and in dire humanitarian need. Civilians and civilian infrastructure are not a target."

Natalia Humeniuk, spokesperson for Ukraine’s southern military command, said: “This is a hysterical reaction.

“They (Russia) were aware that the movement of the defence forces would take place, and in this way tried to influence the defence forces so that the crossing of the Dnipro river, which they feared, would not happen.”

• Ukraine accuses Russia of destroying major dam near Kherson, warns of ecological disaster (AP, 5 min)

Why are there nuclear concerns?

The dam's reservoir provides cooling water to the Zaporizhzhia Nuclear Power Plant, about 100 miles upstream, which is under Russian control.

However, Ukraine's state nuclear power agency and the United Nations nuclear watchdog both said there was no immediate nuclear safety risk.

Energoatom, Ukraine's nuclear power agency, said Russia had blown up the dam.

"Water from the Kakhovka reservoir is necessary for the station to receive power for turbine capacitors and safety systems of the Zaporizhzhia Nuclear Power Plant (ZNPP)," it said in a statement.

"Currently, the situation at the ZNPP is under control, Ukrainian personnel are monitoring all indicators."

The UN's nuclear watchdog, the International Atomic Energy Agency (IAEA), said its experts at the plant were monitoring the situation closely.

It said: "The IAEA is aware of reports of damage at Ukraine’s Kakhovka dam. IAEA experts at Zaporizhzhia Nuclear Power Station Nuclear Power Plant are closely monitoring the situation, no immediate nuclear safety risk at plant."

• Situation at nuclear plant 'under control' after Ukraine dam blast (Reuters, 1 min)

Watch: Foreign secretary condemns Russia for 'unprovoked' attack on dam