Ukraine’s human rights ombudsman has denounced the alleged execution of nine captured Ukrainian troops by Russian forces in the Kursk border region.

Dmytro Lubinets said he had written to the United Nations and the Red Cross about the allegations, accusing Moscow of breaching “all the rules and customs of war”.

The intervention follows reporting by Ukrainian battlefield analysis site DeepState, which published drone footage purporting to show the dead troops who it said were drone operators. Officials in Russia have yet to comment on the allegations.