Ukrainian officials say more than 19,000 children have been unlawfully deported to Russia or occupied areas, with reports suggesting the number could be far higher.

NATO defence chiefs were due to hold a virtual meeting on Wednesday, a senior alliance official said, as countries pushing for an end to Russia’s war on Ukraine devise possible future security guarantees for Kyiv that could help forge a peace agreement.

Russia said Wednesday attempts to resolve security issues relating to Ukraine without Moscow's participation were a "road to nowhere," and that much diplomatic work needs to be done before Vladimir Putin and Volodymyr Zelenskyy are ever in the same room.