Russian president says beginning of offensive ‘is evidenced by the use of strategic reserves’. This live blog is closed

• Seismic data adds to evidence Ukraine’s Kakhovka dam was blown up

Russian military bloggers are saying that overnight the Ukrainians were making another attempt to break through Russian lines in occupied Zaporizhzhia in the area of Orikhiv.

The claims have not been independently verified.

Agriculture ministry warns of greater disaster next year, with global implications, from loss of Kakhovka reservoir

• Russia-Ukraine war live

The fields of southern Ukraine could “turn into deserts” by next year, the country’s agrarian and food ministry said after the destruction of the Kakhovka dam and the draining of its reservoir, which had irrigated one of the world’s breadbaskets.

Ukrainian emergency services and aid organisations carried out a second day of rescue operations to help the 42,000 people estimated to be at immediate risk from flooding downstream of the dam, including making some forays to the Russian-occupied left bank of the Dnipro River to save people cut off in flooded towns.

Secretary of Ukraine’s National Security and Defence Council dismisses claim counteroffensive has begun; Rishi Sunak says UK ‘can’t say definitively’ whether Russia was responsible

• People in Ukraine: do you live near the Nova Kakhovka dam?

Neither the French, US or British representatives at the UN directly said there was evidence of Russian responsibility, but called for an investigation and insisted their support for Ukraine was unwavering.

Outside the UN security council chamber on Tuesday, the deputy US ambassador to the UN, Robert Wood, said: “We’re not certain at all, we hope to have more information in the coming days.

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• Russia-Ukraine war live updates: thousands evacuated amid flooding as UN says scale of dam disaster will only be clear in coming days – latest news
• People in Ukraine: do you live near the Nova Kakhovka dam?

Ukraine’s National Police force are asking people in affected villages to evacuate.

The Police said on Telegram a moment ago:

Units of the National Police and the State Emergency Service of the Kherson region were alerted to alert and evacuate the civilian population from potential flooding zones on the right bank of the Dnieper River, namely: the villages of Mykolaivka, Olhivka, Lyovo, Tyaginka, Poniativka, Ivanovka, Tokarivka, Poniativka, Prydniprovske, Sadove and partly the city of Kherson - Korabel Island.

The water level is rising and everyone who is in the danger zone must:

❗️ In the Kherson region, the settlements on the right bank of the Dnieper have been named as being at risk of flooding

Evacuation of the civilian population from potential flood zones on the right bank of the Dnieper River is underway, namely:

Ukraine accuses Russia of blowing up Nova Kakhovka dam; people in parts of Kherson and the surrounding area urged to evacuate

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Ukraine president Volodymyr Zelenskiy’s chief of staff says he ‘does not understand’ how there are any doubts that Russian forces blew up the dam. In a statement, Andriy Yermak said: “At 2.50am, Russian troops blew up the Kakhovka hydroelectric station and its dam. I do not understand how there can be any doubt about this. Both constructions are located in the temporary Russian-occupied territories. Neither shelling nor any other external influence was capable of destroying the structures. The explosion came from within.”

The Kremlin accuses Ukraine of deliberately sabotaging the dam. Dmitry Peskov, the Kremlin’s spokesperson, told reporters: “We can state unequivocally that we are talking about deliberate sabotage by the Ukrainian side.” He said [Russian president] Vladimir Putin had been briefed on the situation.

The US “cannot say conclusively” who was responsible. National Security Council spokesperson John Kirby told reporters at the White House: “We’re doing the best we can to assess”, noting “destruction of civilian infrastructure is not allowed by the laws of war”. Earlier Tuesday, NBC News reported that the US government had intelligence indicating Russia was behind the incident, according to two US officials and one western official.

The Ukrainian government called for people living downstream to evacuate in the face of catastrophic flooding. Energy company Ukrahydroenergo said the hydroelectric power plant at the dam had been blown up from the inside and was irreparable.

The governor of the Kherson region, Oleksandr Prokudin, said about 16,000 people were in the “critical zone” on the Ukrainian-controlled right bank of the river.

The areas most under threat of flooding are the islands along the course of the Dnipro downstream of Nova Kakhovka and much of the Russian-held left bank in southern Kherson. Andrey Alekseyenko, one of the Russian-installed officials in occupied Kherson, has posted to Telegram to say that up to 22,000 people are in the flood plains in Russian-controlled territory.

Hanna Maliar says Kyiv’s forces are moving to ‘offensive actions’, heightening speculation that a counteroffensive is close to launch. This live blog is closed

• At a glance: what we know on day 466 of the invasion

At least 90 supporters of jailed opposition leader Alexei Navalny were reportedly arrested on Sunday after defying authorities to hold demonstrations to mark his 47th birthday, the Associated Press has said.

Navalny is serving a nine-year sentence for fraud and contempt of court, charges he says were trumped up to punish him for his work to expose official corruption and organise anti-Kremlin protests. He is facing a new trial on extremism charges that could keep him in prison for decades.