ANKARA, May 31. /TASS/. Ankara is working to make sure that Russia and Ukraine hold talks in Istanbul, Turkish President Recep Tayyip Erdogan said in a phone call with his Bulgarian counterpart Rumen Radev.

"President Tayyip Erdogan of Turkey has held a telephone conversation with President Rumen Radev of Bulgaria. Our president stated that efforts were underway to end the war between Ukraine and Russia as Bulgaria was seen pursuing a careful policy on the issue and Turkey was working to bring the parties together in Istanbul to ensure peace in the region," Erdogan’s office said in a statement.

The two presidents also discussed "bilateral relations between Turkey and Bulgaria, as well as regional and global issues." "Erdogan stated that Turkey-Bulgaria relations continued to develop and efforts were made to boost defense and energy cooperation," the statement added.

Russian Foreign Minister Sergey Lavrov announced earlier that the second round of the Istanbul talks with Ukraine was set for June 2. The top diplomat said that the Russian delegation’s head, Vladimir Medinsky, would deliver Moscow’s memorandum on all aspects of overcoming the underlying causes of the crisis over to Ukraine. The previous round of talks was held on May 16, resulting in agreements on a 1,000-for-1,000 prisoner swap and an exchange of documents on a potential ceasefire. Both parties expressed satisfaction with the outcome of the meeting.