KYIV, Ukraine, June 1, (AP): A Ukrainian drone attack has destroyed more than 40 Russian planes deep in Russia’s territory, a Ukrainian security official told The Associated Press on Sunday, while Russia pounded Ukraine with missiles and drones a day before the two sides meet for a new round of direct talks in Istanbul.

The official, who spoke on condition of anonymity to disclose operational details, said the attack took over 1 1/2-year to execute and was personally supervised by Ukrainian President Volodymyr Zelenskyy. The operation saw drones transported in containers carried by trucks deep into Russian territory, he said. The drones hit airfields including the Belaya air base in Russia’s Irkutsk region, more than 4,000 kilometers (2,500 miles) from Ukraine. It is the first time that a Ukrainian drone has been seen in the region, local Gov. Igor Kobzeva said, stressing that it did not present a threat to civilians.

The attack was disclosed on the same day as Zelenskyy said Ukraine will send a delegation to Istanbul for a new round of direct peace talks with Russia on Monday. In a statement on Telegram, Zelenskyy said that Defense Minister Rustem Umerov will lead the Ukrainian delegation. "We are doing everything to protect our independence, our state and our people,” Zelenskyy said.

Ukrainian officials had previously called on the Kremlin to provide a promised memorandum setting out its position on ending the war before the meeting takes place. Moscow had said it would share its memorandum during the talks. Russia on Sunday launched the biggest number of drones - 472 - on Ukraine since the full-scale invasion in February 2022, Ukraine’s air force said.