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.

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.

The second Oval Office meeting in six months between U.S. President Donald Trump and Ukrainian President Volodymyr Zelenskyy went off smoothly, in sharp contrast to their disastrous encounter in February.