After a fraught few hours, Nato said the missile that hit Poland - one of its members - was most likely fired by Ukraine in defence. The organisation says it was not intentional.
We hear reaction from Ukraine, the US and Russia, with analysis from the BBC’s Security Correspondent Frank Gardner and Sam de Bendern , a political analyst with Chatham House and a former adviser to Nato.
We also hear a moving account of life on the front line from a team of Ukrainian medics in the Donbas.
Today’s episode is presented by the BBC’s chief international correspondent, Lyse Doucet, and Vitaliy Shevchenko, the head of the BBC’s Russia monitoring team.
The producers were Arsenii Sokolov, Clare Williamson, Luke Radcliff and Fiona Leach. The technical coordinator was Mike Regaard. The series producer is Estelle Doyle. The assistant editor is Alison Gee. And the editor is Jonathan Aspinwall.
Email Ukrainecast@bbc.co.uk with your questions and comments. You can also send us a message or voice note via WhatsApp, Signal or Telegram to +44 330 1239480.