Ukraine announced on Sunday that it carried out a “large-scale” drone attack targeting Russian military aircraft deep inside Russian territory, just a day before scheduled ceasefire talks in Istanbul.

Ukrainian security sources claim the strikes hit airbases in Belaya (eastern Siberia), Olenya (near Finland), Ivanovo, and Dyagilevo, damaging or destroying more than 40 aircraft in one location alone.

The operation reportedly inflicted approximately $2bn in damages.

AFP was not able to independently verify the claims or the video images.

Russia also said two bridges that collapsed in regions bordering Ukraine were brought down by explosions. Officials were treating them as “acts of terrorism” but had not immediately accused Ukraine.

The escalation came as Ukrainian President Volodymyr Zelensky prepares to send a delegation to peace talks in Turkey, led by Defence Minister Rustem Umerov.

The meeting, set for Monday, followed a diplomatic push by US President Donald Trump for a swift resolution to the war, which has now entered its third year.

Zelensky stated that Ukraine’s objectives for the talks include securing a “complete and unconditional ceasefire” and the return of prisoners of war and abducted children.

However, he previously expressed doubt over Russia’s commitment to genuine negotiations.

Russian President Vladimir Putin has declined Turkey’s suggestion for a summit at the leadership level and has not publicly disclosed Moscow’s negotiation terms.

Meanwhile, violence on both sides has intensified. Ukraine reported that a Russian missile strike on a military training site killed at least 12 soldiers and wounded over 60.

The attack prompted the resignation of Ukrainian Ground Forces Commander Mykhailo Drapaty, who cited his responsibility for the loss of life.

In Russia, authorities reported the collapse of two bridges near the Ukrainian border, one in Bryansk and another in Kursk.

The Bryansk incident derailed a passenger train, killing seven people, while the Kursk explosion damaged a freight line and injured its operator. Both incidents are being treated as acts of terrorism, although no suspects have been officially named.

Russia continues to advance in Ukraine’s Sumy region, claiming to have seized another village over the weekend. Ukrainian officials warn that Moscow may be preparing for a renewed ground offensive, as more than 50,000 Russian troops are reportedly stationed near the border.

Authorities in the region have evacuated more than 200 villages amid intensified shelling.