Russian and Ukrainian delegates met in Istanbul on Monday for their second set of direct peace talks, a day after Kyiv launched a shock drone attack on Russia’s nuclear-capable bombers, in an operation that President Volodymyr Zelensky said was a year and a half in the making.

Ukrainian President Volodymyr Zelensky on Wednesday dismissed Russia’s ceasefire proposal as “an ultimatum” and renewed his call for direct talks with Russian President Vladimir Putin to break the deadlock over the three-year war.

Ukraine suspects Russia is not really interested in pausing the conflict and ending the war, and the head of the country’s delegation, Defence Minister Rustem Umerov, said the key points could only be resolved at face-to-face talks between President Zelensky and President Putin.