4.51am: Summary of what Prime Minister Najib Abdul Razak's press conference at Sama-sama Hotel:
– Ukraine says #MH17 was shot down but Malaysia can't confirm this.
– If the plane was indeed shot down, the perpetrators must be brought to justice.
– #MH17 was travelling in unrestricted airspace. There was no distress call made.
– Kiev has agreed to negotiate with East Ukraine separatists to mark out a "humanitarian corridor" to allow access to the crash site.
– Malaysia is sending a special despatch to Kiev for the purpose of the search and recovery effort.
– President Obama, when speaking to Najib, also agreed that the crash site should not be interfered with.
– Malaysia will get to the bottom of the tragedy and leave "no stone unturned".
"This has been a tragic year for Malaysia," he said.