Ukrainians endured power curbs including the first blackouts imposed by grid authorities since the war began to allow the repair of infrastructure destroyed by Russian air strikes as Kyiv's forces pressed on towards the city of Kherson.
Although Ukraine is advancing against Russian troops in the east and the south, it is struggling to protect power generating facilities and other utilities from missile and drone strikes that appear designed to disrupt and demoralise as winter approaches.
People across the country were urged to use less power as the government enforced nationwide curbs on electricity usage between 7am and 11pm, the first such restrictions since Russia's 24 February invasion and including blackouts in some areas.
That followed a barrage of Russian attacks that President Volodymyr Zelensky said had struck a third of all power plants.
The president accused Russia of planting mines at a hydroelectric plant dam in the Kherson region of southern Ukraine, which is under the control of Moscow's forces.
"According to our information, the aggregate and dam of the Kakhovka hydroelectric power plant were mined by Russian terrorists," Mr Zelensky said in his daily address.
"If the dam is destroyed... the North Crimean canal will simply disappear", and this would be "a catastrophe on a grand scale", he added.
The dam of the Kakhovka hydroelectric power station is built on the Dnieper river, in an area currently under the control of the Russian army and not far from the line of contact with Ukrainian forces.
Meanwhile the northeast region of Sumy went without water as some Kyiv grocery stores reported sales of bottled water picking up in preparation for possible shortages there.
"There is much anger against Russian leaders and Russian people," Mikhaylo Holovnenko, a Kyiv resident, told Reuters.
"But we are ready for outages. We have candles, charged power banks. Ukraine is charged to win."
The northeast region of Sumy went without water as some grocery stores in the capital Kyiv reported sales of bottled water picking up in preparation for possible shortages.
Russian President Vladimir Putin on inspected a training ground for mobilised troops in Ryazan, southeast of Moscow, and was shown firing shots from a sniper rifle in footage apparently intended to show his personal backing for soldiers heading to fight in Ukraine.
Russia's defence ministry said it was again targeting Ukrainian energy infrastructure, a strategy it has stepped up since the appointment this month of Sergei Surovikin.
In two video addresses Mr Zelensky, without providing evidence, accused Russia of preparing to cause a large-scale disaster in southern Ukraine.
Ukraine has information that Russian forces have mined the dam and units of the Kakhovska hydroelectric power station, Zelensky asserted, adding that 80 settlements, including the strategic city of Kherson, could experience rapid flooding.
Mr Zelensky said that if Russia "is seriously considering such a scenario, it means that the terrorists are very clearly aware that they cannot hold not only Kherson, but also the entire south of our country, including Crimea."
The Ukrainian military continued to try to press its advance towards Kherson, the only regional capital Russian forces have captured.
Kherson residents were shown on footage taken by Russian media gathered at the city river port waiting in long queues to board boats to get to the left, eastern bank of the Dnipro River which bisects Ukraine.
Olaf Scholz, the German chancellor, accused Russian President Vladimir Putin of using energy and hunger as weapons.
"Scorched earth tactics will not help Russia win the war. They will only strengthen the unity and resolve of Ukraine and its partners," Mr Scholz told the German parliament.
Dmitry Medvedev, deputy head of Russia's Security Council, said Mr Scholz had "clearly forgotten the Nazi past of his country and the 30 million Soviet people who were killed or died of hunger and cold during the war."
Russia's defence ministry said it was again targeting Ukrainian energy infrastructure, a strategy it has stepped up since the appointment this month of Sergei Surovikin - nicknamed "General Armageddon" by the Russian media - as commander of what Moscow calls its "special military operation" in Ukraine.
and declared martial law yesterday in areas of Ukraine occupied by his forces
Ukrainian Energy Minister Herman Halushchenko told national TV that Russia had carried out more than 300 air strikes on Ukrainian energy facilities since 10 October.
He said the government was seeking a 20% reduction in energy use as a result.
"We see a voluntary decrease (in electricity consumption). But when it is not enough, we are forced to bring in forced shutdowns," he said.
Kyiv and Kharkiv announced curbs on the use of electric-powered public transport such as trolleybuses and reduced the frequency of trains on the metro.
"We need time to restore power plants, we need respite from our consumers," Volodymyr Kudrytskyi, head of grid operator Ukrenergo, told Ukrainian TV.
Iranian drones?
The United States said that Iranian military trainers had been sent to Crimea to assist Russian forces using Iranian-made drones to attack targets in Ukraine, adding a new international element to a war that has already worsened some geopolitical tensions.
"We can confirm that Russian military personnel based in Crimea have been piloting Iranian UAVs and using them to conduct kinetic strikes across Ukraine, including in strikes against Kyiv in recent days," US State Department spokesman Ned Price told a daily briefing with reporters, referring to unmanned aerial vehicles, or drones.
"We assess that... Iranian military personnel were on the ground in Crimea and assisted Russia in these operations," Mr Price said.
Russia's defence and foreign ministries did not immediately respond to requests for comment.
White House national security spokesperson John Kirby told reporters that Washington is going to pursue all means to "expose, deter and confront" Iran's supply of munitions to Russia, including more sanctions, while also considering air defence solutions for Ukraine.
European Union members have agreed on new measures against Iran, while Britain imposed sanctions on senior military figures and a firm it said were involved in the supply of Iranian drones to Moscow.
Earlier today, Mr Zelensky told the European Union that "Russia's leadership has given the order to turn the energy system itself into a battlefield."
Speaking via video link, he warned that this would spur a new wave of Ukrainian refugees fleeing to Europe.
"The consequences of this are very dangerous, again for all of us in Europe," he told EU leaders meeting in Brussels for a summit.
Leaders of the 27 member states discussed options for more support to Ukraine, including energy equipment, helping restore power supply and long-term financing to rebuild.
Much of the destruction has been inflicted by Russian drones, which Ukraine and the West say are Iranian-made, something Tehran denies.
On the ground, the Ukrainian military continued to try to press its advance towards the southern city of Kherson, the only regional capital Russian forces have captured.
The Russian-appointed administration yesterday told civilians to leave the city - control of which gives Russia a land route to Crimea, which it seized in 2014, and the mouth of the Dnipro river.
Ukraine's military said in an update on the Kherson region that 43 Russian servicemen had been killed and six tanks and other equipment destroyed.
The Russian defence ministry described a battle in the area which it said its forces had won.
Reuters was not able to verify battlefield reports.
