Russian troops launched some 109 drones and five missiles across Ukraine overnight and into Saturday, the Ukrainian air force said.

Kremlin spokesperson Dmitry Peskov stressed that a high-level summit would require concrete outcomes from the negotiations between the Russian and Ukrainian delegations.

A statement on the ministry's website said Lavrov told Rubio about the implementation of agreements between the Russian and U.S. presidents during their telephone call a week ago "and preparations by the Russian side of concrete proposals for the next round of direct Russian-Ukrainian talks in Istanbul.

Ukraine is ready to resume direct peace talks with Russia in Istanbul on Monday, a top adviser to President Volodymyr Zelenskyy said, following days of uncertainty over whether Kyiv would attend a further meeting proposed by Moscow.

Turkish Foreign Minister Hakan Fidan is expected to visit Ukraine later this week after his two-day trip to Moscow, Reuters reported on May 27, citing a Turkish Foreign Ministry source. Fidan, whose country hosted the first direct peace talks betweenRussia and Ukraine in three years,