The retreat follows recent blasts at Russian military bases in Crimea which Ukraine has claimed responsibility for.
“The occupiers are carrying out measures to partially transfer aviation equipment from forward-based airfields in Crimea to reserve airfields and airfields permanently based on the territory of the Russian Federation,” Ukrainian military intelligence said.
“Such activity was noted after a series of explosions at the military infrastructure facilities of the temporarily occupied Crimea peninsula, including at the airfields Saki and Gvardiyske.”
Russia is believed to have lost at numerous warplanes last week when explosions rocked the Russian-operated Saki airfield on the west coast of the peninsula which was annexed by Russia in 2014.
Explosions were also reported in Crimea this week at an ammunition depot and at another airfield.
A Ukrainian government report has reportedly emerged confirming Kyiv’s forces were behind the attacks, following initial denials of responisbility.
It comes as Ukrainian president Volodymyr Zelensky was set to meet UN secretary general Antonio Guterres and Turkish President Tayyip Erdogan in the western city of Lviv on Thursday afternoon.
President Zelensky wants help from the UN dealing with what he has warned is the risk of disaster at Zaporizhzhia, Europe’s largest nuclear plant.
On Thursday Russia denied having any heavy weapons near the facility and accused Kyiv of a “provocation”.
Also on the agenda was addressing the threat to global food supplies raised by the near-six-month war.
This morning one person was killed and another 18 were wounded in pre-dawn shelling in the eastern city of Kharkiv, just a day after a rocket attack claimed the lives of six civilians in the city.
Ukrainian presidential adviser Oleksiy Arestovych said: “Russian forces have achieved only minimal advances, and in some cases we have advanced, since last month.
“What we are seeing is a ‘strategic deadlock’.”