Russia's defence ministry has accused Ukrainian "saboteurs" of blowing up a section of the Togliatti-Odesa pipeline in the north-eastern Ukrainian region of Kharkiv on Monday.

The pipeline - the longest in the world of its kind - was used by Russia before the war to export ammonia, a key chemical compound in agricultural fertiliser.

But Ukraine has accused Russia of firing at the pipeline. The BBC has not independently verified the claims.

There’s been talk for a while now about Ukraine’s long-anticipated counter-offensive.

According to Oleksiy Danilov, the secretary of Ukraine’s National Defence Council, it hasn’t started yet. Speaking to the Reuters news agency, he dismissed statements from Russia that the manoeuvre had begun, saying: "All of this is not true."

Earlier this week Moscow said it had thwarted a major Ukrainian offensive in Donetsk - something the BBC has not independently verified. Kyiv declined to comment.

Bakhmut in eastern Ukraine is again the subject of claim and counter-claim.

The city has been at the heart of fierce fighting for many months - experiencing the longest and bloodiest battle of the Russian invasion so far.

Military analysts have suggested the city is of little strategic value - but control of the former mining hub has become important symbolically both for Kyiv and Moscow.

There is little of Bakhmut still standing - after heavy shelling devastated the city's buildings and drove out its residents - but the Russian mercenary group Wagner claimed to have captured what remained of it late last month.

In recent weeks, some have suggested Kyiv's forces have been attempting to encircle Bakhmut and trap Russian units. Military activity in the area has stepped up significantly over the last few days.

• Read more

Image source, Reuters

As has been typical of the battle for Bakhmut so far, both sides have claimed victory in offensives around the devastated city in eastern Ukraine.

While the Ukrainians say they've made advances of up to 1.1km (0.7 miles) in the direction of the city, Russia says it has defeated its enemy's attacks near the city.

The defence ministry says Ukrainian forces mounted a series of "unsuccessful offensives" in the area - which has seen some of the deadliest fighting of the war.

The BBC has not been able to independently verify either side's claims.

The Kakhovka dam disaster was front-page news in most Russian media this morning, except for Rossiyskaya Gazeta - the official newspaper of the Kremlin - which relegated the story to page three in favour of a story about rubbish.

The paper sticks to the Russian government's line that Ukraine is responsible for blowing up the dam.

Our Russia editor, Steve Rosenberg, has taken a look at how Russian media have covered the story. You can watch below:

Image source, Ukrainian Armed Forces Press Service/Reuters

As our diplomatic correspondent Paul Adams wrote earlier, the breach of the Kakhovka dam came just a day after Ukraine’s long-anticipated counter offensive appeared to get under way. And the country's deputy defence minister has given a fresh update on troop movements today.

Forces have advanced from 200 to 1,100 metres in "various sections of the Bakhmut direction", Hanna Maliar writes on the Telegram messaging app. She says her forces have switched from being on the defensive to the offensive in the area.

Maliar issued a similar update yesterday, without confirming whether the long-anticipated counter-offensive had officially begun.

We can’t independently verify the situation on the battlefield. There's there's been intense fighting in Bakhmut in recent months - and both Kyiv and Moscow have claimed to be in control of the city.

Let's look more broadly at the situation across Ukraine now. Officials have given reports of fresh Russian attacks, with some deaths reported.

At least one person was killed and another injured in a shelling attack on Kherson, while the southern city deals with flooding and evacuations, according to the regional governor.

And a separate attack, using drones, has killed two civilians and wounded one other in the Sumy region in the north-east, according to Andriy Yermak, the head of the president's office.

Image source, Reuters

Here's what we know so far about the situation in southern Ukraine as it stands:

• Ukraine's President Volodymyr Zelensky has said hundreds of thousands of people have been left without drinking water and tens of thousands are still stranded by floodwaters - after a dam in the Russian-occupied town of Nova Kakhovka was breached on Tuesday morning
• Evacuations from the surrounding areas are ongoing, with rising water levels expected to peak in Kherson later today
• Our Ukraine correspondent James Waterhouse is reporting from the city - which was recaptured by Ukraine late last year - and says many homes have been submerged up to their rooftops
• Many people in Kherson spent the night on rooftops and in trees, waiting to be rescued
• But the floods in Nova Kakhovka itself are currently receding, local authorities say
• Warnings have been issued that the falling levels of the Kakhovka reservoir could have a devastating impact on the vast and vital agriculture industry in southern Ukraine, which is reliant on the massive body of water for irrigation
• Fears over the environmental damage from pollution and flooding have also been expressed - with Ukraine describing it as one of the worst environmental catastrophes to hit Europe in decades
• However, there is no immediate threat to the Zaporizhia nuclear power plant upriver, which uses the reservoir to cool its reactors

Residents of a Ukrainian city upriver from the Kakhovka dam have been urged to save water.

Writing on Telegram, Nikopol's mayor Yevhenii Yevtushenko said local authorities were working to ensure enough bottled drinking water was being delivered to local shops. He also warned residents against sharing claims of price-gouging.

Nikopol, which is about 75 miles (120km) upriver from the destroyed dam, is one of many Ukranian cities along the Dnipro river which uses the now-depleting reservoir as their primary source of water.

Yevtushenko said authorities have been monitoring prices in the wider region and had found only isolated cases of people charging much more for water.

Image source, Reuters

Elevated water levels could last up to 10 days in some parts of Ukraine's southern Kherson region, Russian state media has reported.

The flooding is forecast to continue for three to 10 days, according to the emergency services it cites.

There are still a number of unanswered questions about how the dam in Nova Kakhovka was breached. Here's what we know so far:

• The breaching of the dam happened early on Tuesday morning
• As a result, low-lying areas either side of the Dnipro river have been flooded and thousands of people have already been evacuated

• It's unclear when and how the dam was damaged. Ukraine and its military allies have accused Russia of attacking the dam in an attempt to frustrate Kyiv's long-planned counteroffensive. Moscow has claimed it was a "deliberate act of sabotage" carried out by Kyiv to deprive the occupied Crimean peninsula of water
• Satellite images suggest the dam's condition deteriorated over a number of days
• Water levels are expected to peak in the nearby city of Kherson later today, but are receding in Russian-occupied Nova Kakhovka where the dam is located
• Ukrainian officials have warned the ecological damage could last for years

For a more extensive summary of the situation as it stands click here.

Rescue efforts are ongoing to evacuate thousands of people affected by flooding after the dam in Nova Kakhovka was breached yesterday morning.

Ukraine has warned some 42,000 are at risk from flooding.

Image source, Reuters

Image source, Reuters

Image source, Reuters

Image source, Reuters

James Waterhouse
Ukraine correspondent reporting from Kherson

In the drive towards Kherson’s riverbanks, you realise the Dnipro river comes to you. Ahead, rooftops protrude above its brown, cloudy floodwaters.

To the right is the roof of a small truck. Occasionally a small rescue boat weaves through the submerged streets to pull people trapped in their homes.

We meet Viktoria, who’s worried about her neighbours who live towards what is now a watery horizon. Both she and the authorities here are worried the water levels could rise even further.

During my last visit to Kherson at the end of last year, there seemed to be an enduring optimism after the city escaped Russian occupation.

That’s even with the daily shelling this city faced, and still does. However, from listening to Viktoria and her friends, that morale is lower. People here have had enough.

Image source, EPA

Tens of thousands of hectares of agricultural land in southern Ukraine will be flooded as a result of the dam being breached, the country's agricultural ministry has predicted.

It warns that at least 500,000 hectares of land left without irrigation could be turned into "deserts".

That's an area more than three times the size of London, which covers an area close to 160,000 hectares.

In 2021 - before Russia's full-scale invasion - the ministry said the dam system, in Nova Kakhovka, provided irrigation for 584,000 hectares from which farmers harvested about four million tonnes of grains and oil seeds.

The dam's destruction has left 94% of irrigation systems in Kherson, 74% of those in Zaporizhzhia and 30% of those in Dnipro regions without water, the ministry says.

Image source, Reuters

The Ukrainian MP for the country's Odesa region has described the breaching of the dam in Nova Kakhovka as a "catastrophe".

Speaking to BBC Radio 4's Today programme earlier, Oleksiy Goncharenko said the flooding was ongoing "and we don't know when it'll stop, so I can't even say that we've already reached the maximum [amount of water]".

"Thousands of hectares of land are under water and thousands of houses are destroyed," he said, while explaining entire towns and villages have been badly damaged.

"And these are just the short-term consequences - the long term ones will be damage to the environment for years ahead."

Image source, Reuters

As we've been reporting, thousands of people are being evacuated from southern Ukraine's Kherson region after a major dam in the town of Nova Kakhovka was breached yesterday morning.

Hanna Zarudnia, 65, was one of those evacuated from the village of Antonivka - which is just north of the banks of the River Dnipro.

"Our local school and stadium downtown were flooded, the stadium was completely under water and the floodwaters were reaching the school," she told Reuters.

"The road was completely flooded, the bus was stuck. Only one elevated point could be reached by the bus and this is where we were taken from."

Chris Mason
Political editor

UK Prime Minister Rishi Sunak has said if it is proven the dam was breached intentionally, it would represent a “new low” in Russian aggression.

Sunak made the remarks on his way to Washington in which he will discuss the war in Ukraine with US President Joe Biden.

The PM told us the UK’s military and intelligence agencies were looking into what had happened – and so it was too soon to “preempt that and make a definitive judgement.”

But, he added, if it was intentional, it would represent “the largest attack on civilian infrastructure in Ukraine since the start of the war,” and “demonstrate the new lows that we would have seen from Russian aggression.”

Such attacks, he said, were “appalling and wrong.”

Image source, EPA

The remaining structure of the Kakhovka dam is likely to deteriorate further over the next few days, the UK's Ministry of Defence has said.

In an intelligence update posted on Twitter, external, the MoD says the dam partially failed shortly before 03:00 local time on Tuesday and the entire eastern portion of the structure was swept away by midday.

It also says the water level in the Kakhovka reservoir was at a record high shortly before the breach, which led to a "particularly high volume of water inundating the area downstream".

But the MoD also says the Zaporizhzhia nuclear power plant is "highly unlikely" to face immediate safety issues over the dropping water levels in the reservoir.

Image source, EPA

Hundreds of thousands of people have been left without access to normal drinking water since the breach of the Kakhovka dam, Ukraine's President Volodymyr Zelensky has said.

He said at least "tens of thousands" of people are still stranded in the area.

Writing on Telegram this morning, he said: "Our services, all those who can help people, are already involved. But we can only help on the territory controlled by Ukraine.

"On the part occupied by Russia, the occupiers are not even trying to help people."

Zelensky condemned the dam attack by saying that it was carried out by Russian forces and was "absolutely deliberate".

"Russian terrorists have once again proved that they are a threat to everything living," he added.

Kyiv and Moscow have accused each other of the dam's breach, and the claims by the warring sides have not been verified by the BBC.

Before and after images show extent of floodingpublished at 08:53 British Summer Time 7 June 2023

08:53 BST 7 June 2023

BBC Verify has looked at more satellite images, revealing the speed and severity of the flooding along the Dnipro River.

Image source, .

The image above shows the village of Korsunka - about 8 miles (13km) from the dam. The "before" image reveals the normal width of the Dnipro River, whereas the "after" image shows heavy flooding by 09:21 BST yesterday.

Image source, .

A terminal used to store grain can be seen in the above satellite image. In the "after" image, a few silos still remain visible by 09:07 BST yesterday despite the heavy flooding.

Image source, .

Finally, this image shows the Kakhovka dam before and after the breach.