Ukraine’s foreign minister on Friday accused Russia of stalling peace negotiations, saying that Moscow had yet to share a promised memorandum outlining its peace terms. He said Kyiv wanted to see that document before sending a delegation to a new round of talks Moscow had proposed for Monday in Istanbul.

A major operation has been launched by Ukraine using drones to destroy Russian bomber planes, according to the Ukrainian security service.

As Ukraine and Russia prepare for peace talks scheduled for June 2 in Istanbul, few observers expect a breakthrough. While the U.S. and Ukraine have pushed for an unconditional ceasefire, the Kremlin has rejected it.

By making harsh, uncompromising demands in peace talks with Ukraine while continuing to pummel it with waves of missiles and drones, Russian President Vladimir Putin is sending a clear message: He will only accept a settlement on his terms and will keep fighting until they’re met.

Russia may find itself in a disadvantageous position in the eyes of the United States if it fails to show flexibility in peace negotiations with Ukraine, states Turkish Foreign Minister Hakan Fidan, according to Anadolu.