Ukraine will send reinforcements to its northern regions and step up diplomatic pressure on Belarus to counter what Kyiv believes are Russian plans to launch a new offensive north of the capital, Volodymyr Zelenskyy has said. Kyiv knew of five scenarios Russia had drawn up, Ukraine’s president added. “We analysed in detail the available data from our intelligence agencies on Russia’s planning of offensive operations in the Chernihiv-Kyiv direction,” Zelenskiy said. “Our forces in this sector will be increased.”

Oleksandr Syrskyi, Ukraine’s top army commander, said Kyiv had data that the Russian general staff was actively calculating and planning offensive operations from the north. The dictator Alexander Lukashenko allowed Russian troops to march on Ukraine from Belarus in 2022. Zelenskyy said it was “already tiresome that there is constantly such a threat to Ukraine that the Russians may at some point drag Belarus into an expansion of the war. They should understand there will be consequences for them and they will be significant.”

In the initial full-scale invasion in 2022, Ukraine successfully repelled a huge Russian armoured column that attempted to attack Kyiv from the north. Ukraine’s border guards spokesperson, Andriy Demchenko, told Ukrinform news agency on Wednesday: “As of now, we haven’t detected any movement of equipment or personnel directly at our border, but of course, we can see the pressure Russia is putting on Belarus.”

Virtually all major oil refineries in central Russia have been forced to halt or scale back fuel output following Ukrainian drone attacks in recent days, Reuters has reported, citing official data and its own sources. The combined capacity of refineries that have fully or partially shut down exceeds 83m tonnes per year, or about 238,000 tonnes per day, accounting for around a quarter of Russia’s total refining capacity. The share of the refineries in Russia’s fuel output is over 30% for gasoline and about 25% for diesel. Moscow has introduced a gasoline exports ban, while the Ukrainian strikes have reduced Russia’s crude oil exports – adding pressure to Moscow’s federal budget, where oil and gas accounts for roughly a quarter of revenue.

Keir Starmer, the British prime minister, spoke to Volodymyr Zelenskyy on Wednesday as the UK government scrambled to reverse a public relations disaster over its latest package of sanctions on Russian oil and gas. After a storm of negative publicity and a row in parliament, Starmer and ministers were forced to spend Wednesday explaining why the package initially exempts diesel and jet fuel made in other countries using Russian oil. Starmer insisted sanctions on those products would be phased in to keep the market stable.

However, Ukrainian officials expressed disappointment, write Peter Walker and Luke Harding. One former senior government figure described western sanctions policy against Russia as “too little too late”. They added: “I’m not sure I understand the logic behind this British decision. The only way Ukraine can stop the war is to put physical sanctions on Russia and destroy its infrastructure.”

Zelenskyy said Ukraine had been in contact with Britain on Wednesday and said the issue of sanctions was “always very sensitive … We conveyed our signals on the matter to London. We expect that everything will be discussed this week on a bilateral level.” Zelenskyy later posted that he had spoken to Starmer by telephone and thanked him for the support provided for Ukraine. The two sides were “working to reinvigorate substantive diplomacy”. No 10 said Starmer had “reaffirmed the UK’s steadfast support for Ukraine”. A spokesperson added that “as a result of the UK’s actions to date, there will be less Russian oil on the market, with Russia weaker as a result”.

The EU is set to disburse €3.2bn to Ukraine next month, the first such payment under a giant loan approved in April, Brussels said on Wednesday.