Russia and Ukraine exchanged more long-range drone attacks that have become a staple of the more than three-year war, officials said Friday, as Russian President Vladimir Putin said Moscow is ready for a fresh round of direct peace talks in Istanbul.

Russia fired a total of 537 aerial weapons, including 477 drones and decoys and 60 missiles, in the "most massive airstrike" since the start of the war, Ukraine's air force said.