Turkish top diplomat sees 'window of opportunity' opening up to settle Ukraine conflict / Russian delegation appears 'decorative', says Ukraine's Zelenskyy / Ukraine's Zelenskyy arrives in Turkey for peace talks, but Russia's Putin is absent / Ukraine war: Zelensky challenges Russia's Putin to talks in Istanbul amid Trump's peace push / Zelensky says Russia sent 'dummy' delegation to Turkey as Ukraine talks set to begin / Russia's stance at Ukraine negotiations shifted due to changes on ground -- Zakharova / Ukraine updates: Zelenskyy slams Putin's absence in Turkey / Zelensky arrives in Ankara ahead of Ukraine-Russia talks, accuses Moscow of sending 'prop' delegation / Europe set to continue, escalate hostilities in Ukraine -- Foreign Ministry / Trump to skip Russia-Ukraine peace talks, calls Zelenskyy the 'greatest salesman, maybe in history'