Chinese-made engines are being covertly shipped via front companies to a state-owned drone manufacturer in Russia, labelled as "industrial refrigeration units" to avoid detection in the wake of Western sanctions,

Russia has deployed its first weapon made entirely of Chinese parts into the Ukrainian airspace in a bid to spook Kiev's air defences.

Russia fired 597 drones and decoys, along with 26 cruise missiles, into Ukraine overnight into Saturday, Ukraine's air force said.

A Russian factory, described by its director as the world's biggest maker of strike drones, has been shown on the Russian army's TV channel with teenagers helping make kamikaze drones to attack Ukraine.