EU hits out at move that Kremlin says is response to countries’ failure to pay in roubles

• Russia-Ukraine war: latest updates

Europe appears to be on the brink of an energy crisis that could further drive up household bills after Russia halted gas supplies to two EU countries and threatened others, in a move condemned by European leaders as blackmail.

The immediate consequence of Gazprom’s decision to stop supply to Poland and Bulgaria while warning other nations opposed to Russia’s war in Ukraine that they could soon be hit was a 20% rise in the wholesale gas price.

In an address in St Petersburg, Vladimir Putin said any countries attempting to interfere in Ukraine or creating “unacceptable strategic threats for us” would be met with a “lightning-fast” response from Moscow. He claimed he had “all the tools for this – ones that no one can brag about … We will use them if needed. And I want everyone to know this. We have already taken all the decisions on this.”

The UN secretary general, António Guterres, arrived in Ukraine committing to evacuate civilians and seek a diplomatic way to end the war, after his controversial meeting with Putin and the Russian foreign minister, Sergei Lavrov, in Moscow on Tuesday.

Serhiy Volyna, the acting commander of the 36th marine brigade in the besieged port city of Mariupol, said hundreds of civilians including children were living in unsanitary conditions and running out of food and water.

The interior ministry of Moldova’s breakaway region of Transnistria issued a statement claiming it had come under attack from Ukraine, raising fears that the country would now be dragged into active conflict.