The Ukrainian government has told US and European bank bosses to sever ties with groups that trade Russian oil, as a top aide to president Volodymyr Zelenskyy accused the lenders of “war crimes”.

Oleg Ustenko, economic adviser to Zelenskyy, wrote to bankers including JPMorgan Chase’s Jamie Dimon and HSBC’s Noel Quinn, asking them to stop financing companies that trade Russian oil and sell shares in state-backed oil and gas groups Gazprom and Rosneft.

In the letters, seen by the Financial Times, which were sent this week and also went to Citigroup and Crédit Agricole, banks were accused of “prolonging” the war by providing credit to companies that ship Russian oil and told they would be blocked from participating in the postwar reconstruction of Ukraine.