Good evening. This is your Russia-Ukraine War Briefing, a weeknight guide to the latest news and analysis about the conflict.

The energy war escalates

Russia lashed out at mounting Western arms shipments and economic penalties by cutting off gas supplies to Poland and Bulgaria, signaling a new phase in the war in which oil and gas supplies are a key part of the battleground.

Since the beginning of the conflict, the U.S. and its allies have attempted to punish Russia while avoiding too much damage to countries like Germany, which still depend on Russian oil and gas. As this newsletter noted last month, Russia needs revenue from oil and gas sales to fund its invasion in Ukraine, while its opponents are vulnerable to price spikes and energy shortages.

Poland’s prime minister, Mateusz Morawiecki, called the gas shut-off “a direct attack.” Poland has been a prime conduit for arms shipments to Ukraine and is sheltering millions of Ukrainian refugees.

Gas prices surged after the cutoff, but the immediate economic impact of the move was limited. Poland has worked for at least a decade to avoid being held ransom by Moscow. Bulgaria, which said Russia was using its gas supplies “as a political and economic weapon,” is more dependent on Russian gas, but it received a pledge of assistance from Greece.

The shut-off serves as a warning of more serious potential gas cutoffs as the war grinds on. It came a day after Germany, which still relies heavily on Russian energy supplies, announced that it would supply its first heavy weapons to Ukraine since the war began.

Germany’s economy minister, Robert Habeck, said today that a sudden halt of Russian gas, which accounts for 35 percent of the country’s supplies, would trigger a recession for Europe’s largest economy. He also said Germany is prepared to seize control of a refinery mostly owned by the Russian energy company Rosneft, which could set the stage for a European Union embargo of Russian oil.

This month, the E.U. approved a ban on Russian coal in response to atrocities that Russian troops carried out in the Ukrainian suburb of Bucha. The U.S., Britain and Canada have already stopped importing oil from Russia, the world’s third-largest producer after the U.S. and Saudi Arabia.

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Flooding a village to keep Russia at bay

The residents of Demydiv, a village north of Kyiv, have been grappling with the aftermath of a severe flood. And they couldn’t be more pleased.

The Ukrainians flooded the village intentionally, along with a vast expanse of fields and bogs around it, creating a quagmire that thwarted a Russian tank assault on Kyiv and bought Ukraine’s army precious time to prepare defenses, my colleague Andrew E. Kramer reports, with photographs and video by David Guttenfelder.

“Everybody understands and nobody regrets it for a moment,” said Antonina Kostuchenko, a retiree, whose living room is now a musty space with waterlines a foot or so up the walls.

“We saved Kyiv!” she said with pride.

Since the war’s early days, Ukraine has been swift and effective in wreaking havoc on its own territory as a way to foil a Russian army with superior numbers and weaponry.

Demydiv was flooded when troops opened a nearby dam and sent water surging into the countryside. Elsewhere in Ukraine, the military has, without hesitation, blown up bridges, bombed roads and disabled rail lines and airports. The goal has been to slow Russian advances, channel enemy troops into traps and force tank columns onto less favorable terrain.

What else we’re following

• Russia is making slow, measured advances on the ground in eastern Ukraine as its forces confront entrenched Ukrainian troops.

• The U.S. is giving Ukraine “detailed intelligence about exactly when and where Russian missiles and bombs” were going to strike, NBC News reports.

• Russia is using cyberattacks in Ukraine to support military strikes, according to Microsoft researchers.

• A Ukrainian commander in Mariupol said that more than 600 civilians and fighters are injured in the Azovstal steel works, the Guardian reports.

• The U.N. humanitarian mission in Ukraine said it expects more than 24 million people, over half the country’s population, will need assistance this year.

Thanks for reading. I’ll be back tomorrow — Adam