World leaders have suggested It's "highly likely" a Ukrainian plane that crashed near Tehran was brought down by an Iranian missile.
Ukranian investigators have arrived in Tehran to examine the crash site and evidence
Iran has denied the claim and invited US, Canadian and French authorities to take part in the crash investigation.
All 176 people on board died in the incident.
Sky's defence and security correspondent Alistair Bunkall walks us through footage reportedly showing the missile hit.