Ukraine says it has recovered the bodies of 563 soldiers from Russia, including over 400 soldiers who fell in the Donetsk region and in the Bakhmut section of the front line.
The remains of more than 150 others were handed over from morgues in Russia, authorities said on Friday. It was not disclosed where these soldiers were killed.
Local media reported that Russia received the remains of 37 soldiers in return.
According to official figures, more than 2100 bodies have been returned to Ukraine this year alone.
The exchange of fallen or captured soldiers is one of the last remaining humanitarian contacts between the warring countries.
Meanwhile, fighting continued in eastern Ukraine on Friday, with the general staff in Kiev recording 114 attacks by Russian troops.
"The enemy is using all available forces and means to achieve its goals," Ukrainian military leadership said, adding that 114 Russian attacks were recorded.
The main flashpoints were once again the districts of Pokrovsk and Kurakhove, west of Donetsk.
The UK Defence Ministry said the number of Russian drone attacks on Ukraine has increased sharply in the last month, with around 2000 unmanned combat drones used against Ukrainian targets in October, up from 700 in September.
It said the number continues to increase and that "it is likely that the high figures seen through September and October to date will become normal."
The ministry attributed the increase to high Russian investments in various types of drone and an expansion of launch sites, which are easy to re-establish if targeted.
If drone production continues unhindered, a shortage of personnel would be the most likely factor limiting more widespread use, it said.
Earlier, at least 25 people were injured in a residential neighbourhood of the north-eastern Ukrainian city of Kharkiv when a Russian air strike targeted the city overnight, authorities said on Friday morning.
The entrance of a multi-storey residential building has been partially destroyed, the military governor of the region, Oleh Syniehubov, wrote on Telegram.
Thirty residents were evacuated overnight due to the risk of the building collapsing, he added.
Nearby buildings, vehicles and the entrance to an underground train station were also damaged.
Russia again used powerful guided bombs to attack Ukraine's second largest city, with further damages to buildings, businesses, vehicles and another train station recorded in another centrally located neighbourhood.
Kharkiv is located close to the Russian border and has come repeatedly under attack since Moscow launched its full-scale invasion of Ukraine on February 24, 2022.
Russia controls around one-fifth of Ukrainian territory, including the Crimean Peninsula, which it annexed in 2014.
