ANKARA, June 15 (Reuters) - Foreign Minister Hakan Fidan will repeat Turkey's offer to host talks between Russia and Ukraine on a visit to Moscow this week at which he will also discuss Black Sea shipping safety and the South Caucasus, a diplomatic source said on Monday. The visit on Tuesday and Wednesday comes ahead of Turkey hosting a NATO summit on July 7-8, and after Kyiv asked Ankara in April to mediate by hosting a leaders' level meeting. Turkey has maintained cordial ties with Moscow and Kyiv since Russia's invasion in 2022.