KYIV / ANKARA- Ukrainian Foreign Minister Dmytro Kuleba did not rule out negotiating with Russia following a high-level conference on peace slated for next month in Switzerland, a Ukrainian news website reported on Thursday.

"In the end, you cannot put the war to an end without both parties," the TSN.ua quoted Kuleba as saying.

Earlier in the day, the Ukrainian presidential press service said that the peace conference will be held on June 15-16 at the Burgenstock resort near the Swiss city of Lucerne.

Tensions between the United States and Türkiye escalated in 2017 when Ankara and Moscow struck the S-400 deal. Washington claimed that the S-400 system would be incompatible with the NATO system and could expose its confidential military information to Russia

State leaders and heads of governments from around the globe were invited to participate in the conference. 

Separately, Turkish Defense Minister Yasar Guler on Thursday ruled out the possibility of transferring the Russian-made S-400 missile defense system to any other country, including Ukraine.

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"Giving our S-400 system to any other country is out of the question," the minister said in an interview with the CNN Türk broadcaster when asked if Ankara had received any proposal to transfer the S-400 system to Ukraine.

The United States had proposed Türkiye to send the S-400 system to Ukraine, but Ankara rejected the proposal, former Turkish Foreign Minister Mevlut Cavusoglu said in May last year.

Tensions between the United States and Türkiye escalated in 2017 when Ankara and Moscow struck the S-400 deal. Washington claimed that the S-400 system would be incompatible with the NATO system and could expose its confidential military information to Russia.

Washington later halted the delivery of F-35 fighter jets to Türkiye and imposed sanctions on the country for purchasing a Russian-made defense system.