The U.N. Human Rights Monitoring Mission in Ukraine said in a report published Thursday that short-range drone attacks killed at least 395 civilians and injured 2,635 between the start of the war and last April. Almost 90% of the attacks were by the Russian armed forces, it reported.

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.

Vladimir Putin has lost four warplanes worth £37 million each despite stepping up their defences after Ukraine’s Operation Spiderweb. A pair of Su-34 fighters were destroyed and two more damaged after an attack on on Marinovka military airfield in Volgograd.