Britain's defense secretary says it is probable that hundreds of North Korean combat troops have started moving to Russia to support Moscow's invasion of Ukraine.

John Healey's remark came after South Korea's National Intelligence Service revealed that North Korea had dispatched about 1,500 soldiers to Russia's Far East this month. It indicated that they may be deployed to the battlefront in Ukraine.

Healey told the Parliament on Tuesday that "it is now highly likely that the transfer of hundreds of combat troops from North Korea to Russia has begun."

He also pointed out that "North Korean soldiers supporting Russia's war of aggression on European soil" is "as shocking as it is desperate."

A Russian independent media outlet has posted a video online showing what it says is a group of North Korean soldiers in camouflage.

Analysis of the footage reportedly identified the location as a military base in Sergeyevka in Russia's Far East.

The author of the video said, "Handsome allies have arrived from North Korea," and expressed hope that this would be the end of the war.

Meanwhile in Ukraine, Prosecutor General Andriy Kostin announced his resignation on Tuesday following allegations that prosecutors and other local officials had lied about the severity of their disabilities to avoid military service.

Kostin became the prosecutor general in July 2022. He had been working with the International Criminal Court to investigate war crimes in Russia.