Kyiv, Ukraine - Russia has sent some of the thousands of Ukrainian children it has abducted from occupied territory to North Korea for "re-education", Ukraine's human rights ombudsman said Thursday.

The official, Dmytro Lubinets, did not say how many children Russia had taken to North Korea – a highly repressive autocracy that has intensified cooperation with Moscow in recent years – and Russia made no immediate public comment.

Citing testimony published by a Kyiv-based human rights group, Lubinets said there was a network of 165 "camps" where Russia was attempting to re-educate the children – in occupied Ukraine, Belarus, and Russia, as well as in North Korea.

A representative from the Regional Center for Human Rights – who Lubinets was citing – reported in testimony to the US Senate on Wednesday that at least some of the children were sent to the Songdowon summer camp on North Korea's eastern coast.

There, they were taught to "destroy Japanese militarists" and met Korean veterans responsible for seizing a US spy ship in 1968.

The Ukrainian government says Russia has abducted or forcibly displaced almost 20,000 children since launching its full-scale invasion in 2022.

Russia has acknowledged moving some children since launching its offensive, but says it did so for their own safety and is trying to reunite them with their families – an assertion Ukraine rejects.

The International Criminal Court issued an arrest warrant for Russian President Vladimir Putin and his children's rights commissioner in 2023 over the alleged deportation and transfer of children to Russian-controlled territory.