Ukraine has carried out one of its deepest strikes into Russian territory, targeting St. Petersburg - a city more than 1,500 kilometers from the front line. Thick smoke rose over key infrastructure, including an oil terminal, as President Volodymyr Zelenskyy described the attacks as “fair” and warned that more could follow. The strike comes just days after deadly Russian attacks on Ukrainian cities. Is this the start of a new phase of escalation in the war? DW Riga bureau chief Juri Rescheto