Ukrainian President Volodymyr Zelenskyy said Tuesday he would attend talks with Moscow on the war in Ukraine this week only if Vladimir Putin is also there, and goaded him by saying the Russian leader was scared to meet him face-to-face.

The Kremlin has yet to say whether Putin will take part in the talks scheduled to be held in Istanbul on Thursday, more than three years into the deadliest conflict in Europe since World War II.

The planned talks have become the main focus of peace efforts led by U.S. President Donald Trump, who said he would send Secretary of State Marco Rubio and has also offered to attend.